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title: "The Nuclear Cascade: How the World Could Have Twenty Nuclear Powers by 2040"
description: "Mutually assured destruction has kept the global order intact since the dawn of the nuclear age — a grim but effective equilibrium among nine nuclear-armed states. Yet in early 2025, that equilibrium is showing unmistakable signs of strain. Poland's prime minister has publicly called for his nation to pursue nuclear capabilities, South Korea's defense establishment is treating a homegrown deterrent as a serious policy option, and Iran is believed to be mere weeks of enrichment away from weapons-grade uranium. Arms-control experts warn that if even one of these nations crosses the threshold, a nuclear cascade could follow — a chain reaction of proliferation in which state after state races to acquire the bomb. The result, in a worst-case but increasingly plausible scenario, could be a world with twenty or more nuclear powers before 2040.\n\n## Key Takeaways\n- Poland, South Korea, and Iran are the three most immediate candidates for nuclear acquisition, each with varying timelines but all potentially capable of producing warheads by or before 2030.\n- A major driver behind Polish and South Korean interest is eroding confidence in the United States' willingness to honor its security commitments under the Trump administration, pushing allies to consider independent deterrents.\n- A nuclear cascade — in which one nation's decision to proliferate triggers others — is the central fear of arms-control experts, and the current geopolitical environment makes such a cascade more plausible than at any point since the Cold War.\n- Turkey, Saudi Arabia, and potentially other Middle Eastern and NATO states could follow suit if Iran, Poland, or South Korea cross the nuclear threshold, dramatically expanding the number of nuclear-armed nations.\n- Existing treaties like the Nuclear Nonproliferation Treaty and the Comprehensive Nuclear-Test-Ban Treaty may prove insufficient to prevent cascading proliferation if major signatories begin defecting from their commitments.\n\n## The Current Nuclear Order and Why It's Under Pressure\n\nThe existing global nuclear architecture rests on a deceptively simple premise: if anyone uses the bomb, everyone uses the bomb. Nine nations — the United States, Russia, China, France, the United Kingdom, India, Pakistan, Israel, and North Korea — currently possess nuclear weapons, and each exists in a deadly serious balance with the others. Russia's use would trigger responses from France and Britain; Pakistan's from India; America's from China and North Korea. This web of mutually assured destruction has held since 1945, but it depends on a relatively small and stable number of actors.\n\nWhat makes the present moment so dangerous is that a growing number of nations outside this club are actively exploring the nuclear option. Iran is reportedly days away from weapons-grade enrichment capability. South Korea is giving serious institutional consideration to a homegrown deterrent. Poland's leadership has made historically bold public statements about pursuing nuclear capabilities. Each of these developments is alarming in isolation, but the real nightmare scenario is a nuclear cascade — one new entrant prompts another, which prompts another, in a self-reinforcing spiral of proliferation that existing treaties and agreements may be powerless to stop.\n\n## Poland: Europe's Aspiring Nuclear Power\n\nIn early March 2025, Polish Prime Minister Donald Tusk made history with an address to parliament in which he called for Poland to build an army five hundred thousand strong and, crucially, to avoid restricting itself to conventional weapons. 'We must be aware that Poland must reach for the most modern capabilities also related to nuclear weapons and modern unconventional weapons,' Tusk declared. 'This is a race for security, not for war.'\n\nTusk explicitly invoked Ukraine's decision to surrender its nuclear arsenal after the Cold War and the devastating consequences that followed at Russia's hands. The parallel is stark: Poland itself hosted Soviet nuclear weapons during the Cold War, but those weapons were removed in 1991. For a nation with deep cultural memory of occupation by Soviets, Nazis, and other powers, the lesson of Ukraine's vulnerability has landed with particular force.\n\nSince Tusk's address, Poland has confirmed its interest in acquiring a nuclear deterrent on its own soil, calling for the United States to deploy nuclear weapons to Poland and deepening conversations with France to the same effect. Yet the option of developing Poland's own warheads remains on the table should allies fail to deliver. Public sentiment supports this trajectory: in February 2025, nearly fifty-three percent of Poles supported the idea of their country acquiring its own nuclear weapons.\n\nLogistically, however, Poland faces significant hurdles. The nation currently has no civilian nuclear power installations, with its first reactors not expected until sometime after 2030. Nor does Poland possess the institutional knowledge that comes with having run a prior nuclear weapons program — it hosted Soviet bombs but never built them. Even on the most aggressive possible timeline, nuclear weapons for Poland are probably at least five years away. There is a slight possibility that France, the United States, South Korea (with whom Poland is building an increasingly close relationship), or another ally could offer support through a joint program or framework of mutual assistance. But 2030 represents the absolute floor for a realistic Polish nuclear capability.\n\n## South Korea: High Nuclear Latency and Growing Resolve\n\nSouth Korea's interest in a homegrown nuclear deterrent has been circulating in public discourse longer than Poland's. In September 2024, then-Defense Minister Kim Yong-hyun raised the possibility during his confirmation hearings, arguing that South Korea should treat nuclear weapons acquisition as a serious option in response to North Korea's nuclear threat. Kim's statement was the latest in a long series of similar remarks by South Korean leaders, all reflecting a growing willingness to pursue an independent deterrent — both to counter Pyongyang and to gain leverage with Washington.\n\nSince January 2025, interest within South Korea has only intensified as demands from Washington prompt experts and policymakers to give the idea serious thought. Public opinion strongly favors the move: a 2024 poll indicated that as much as seventy-six percent of South Koreans would support their country developing its own nuclear weapons. A second poll, summarized in a 2024 Center for Strategic and International Studies report, found support below forty percent — but critically, over half of those opposed said they would change their stance if they became concerned that the United States might renege on its security pledges.\n\nFrom a logistical standpoint, South Korea is far better positioned than Poland. The country exists in a state of high nuclear latency, meaning it possesses the requisite technology, expertise, and state infrastructure to build a bomb if the decision were made. South Korea operated a nuclear weapons program through the 1980s and is among the world's most prolific users of civilian nuclear energy, having built itself into a nuclear reactor exporter. By most estimates, South Korea could produce its first functional warhead within two to three years, though that timeline represents the absolute minimum needed to produce bomb-grade fissile materials. Unlike Japan, which already has over forty-five tons of bomb-grade plutonium set aside, South Korea would need to enrich nuclear material to weapons-grade levels — a process that, while achievable, adds time to the clock.\n\n## Iran: Days Away from Weapons-Grade Uranium\n\nOn the opposite side of the world's geopolitical divides sits Iran, believed to have nuclear breakout capability as of early 2025. According to recent estimates, Iran has accelerated its production of near-weapons-grade uranium — enriching it not quite to the point of weapons-grade, but to a level where only a couple of weeks of additional enrichment would be required to cross that threshold.\n\nHaving weapons-grade uranium, of course, is not the same as having a nuclear bomb. It would take Iran more than a couple of weeks to actually construct a working weapon and integrate a warhead onto a delivery system capable of reaching an enemy target. But even that full capability is estimated to be only a few months away from the moment Iran decides to shift from its current posture to an all-out push. More conservative estimates place the timeline at up to two years. Once a warhead is assembled, Iran already possesses nuclear-capable missiles; the remaining challenge is integration and deployment.\n\nIran's proximity to breakout capability makes it arguably the most immediate proliferation concern among the three leading candidates. Its progress also serves as a powerful catalyst for other nations in the region — particularly Saudi Arabia and Turkey — to accelerate their own nuclear ambitions.\n\n## The Role of American Uncertainty\n\nA common thread running through the nuclear ambitions of Poland, South Korea, and other allied nations is deep uncertainty about the reliability of the United States as a security guarantor. Donald Trump's second term as president has generated widespread concern among US allies, from NATO nations to Taiwan and beyond. These allies fear that Washington under Trump either might not honor its commitments to defend other nations in times of war, or at the very least will refuse to make firm pledges until a crisis actually arrives.\n\nRegardless of what Trump and his inner circle would ultimately choose in a genuine moment of crisis, the ambiguity itself is corrosive. It is pushing nations to think carefully about managing their own defense independently. France and Britain have demonstrated interest in coalition-building without the US. Canada and others are working to reduce dependence on American weapons systems. Poland and South Korea, both rapidly militarizing nations that consider themselves on the front lines of future conflicts — South Korea anticipating confrontation with the North and China, Poland expecting to serve as NATO's primary battlefield in a war with Russia — see a nuclear deterrent as a potentially invaluable tool for demonstrating that they are simply not to be challenged.\n\nThis erosion of confidence in the American nuclear umbrella is not merely a political inconvenience; it is a structural driver of proliferation. When allied nations can no longer trust that the world's largest nuclear power will come to their defense, the incentive to develop independent deterrents becomes overwhelming — and the treaties designed to prevent proliferation lose their most powerful enforcement mechanism.\n\n## Turkey: NATO's Wild Card\n\nIf Poland were to begin working toward nuclear weapons development, one NATO member stands out as a prime candidate to follow suit: Turkey. President Erdogan has hinted at developing the bomb for more than half a decade. In 2019, during a broader dispute with the United States, Erdogan explicitly pushed back against prohibitions keeping Turkey non-nuclear: 'Some countries have missiles with nuclear warheads, not one or two. But we can't have them. This, I cannot accept. There is no developed nation in the world that doesn't have them.'\n\nErdogan has been laying the groundwork for Turkey to develop a deterrent comparable to Israel's. Turkey currently hosts American nuclear warheads and is a signatory to both the Nuclear Nonproliferation Treaty and the Comprehensive Nuclear-Test-Ban Treaty — though, like other nations under discussion, Turkey has not historically been inclined to act against its perceived interests simply to honor international agreements.\n\nTurkey's first civilian nuclear plant is expected to supply up to a tenth of the nation's energy needs, with additional reactors planned. While experts describe the first reactor as 'proliferation-resistant,' it can serve as a valuable experiential teaching tool for Turkish nuclear physicists, making the process of developing a weapon somewhat easier over time. Meanwhile, Turkey appears to be working surreptitiously toward weaponization, reportedly securing mining rights to access uranium in Niger in 2024. The idea of a Turkish bomb has also gained strength among Erdogan's nationalist supporters and is becoming increasingly normalized in Turkish culture.\n\nIn a world where both Poland and Iran are moving toward nuclear weapons, Turkey would likely lose any remaining interest in restraint. A nuclearizing Poland would give Ankara justification to approach alliance members and argue that if the Poles can build a bomb, Turkey should be permitted to do the same. A nuclear Iran would be an even more powerful motivator — if both Iran and Israel were nuclear-armed, it would be extremely difficult to argue that Turkey should refrain from matching them.\n\nPakistan, as part of an emerging strategic alliance with Turkey long suspected to include a nuclear dimension, might even be willing to grant Turkey direct support. As for a timeline, Turkey's path is harder to estimate than other nations due to the proliferation-resistant nature of its current program. Turkey would still need considerable time to enrich weapons-grade uranium, learn to construct an actual warhead, and integrate it onto a delivery system. A rough estimate places Turkey's timeline at longer than three years but less than ten.\n\n## The Rest of Europe: Expansion Rather Than Proliferation\n\nBeyond Poland and Turkey, no other European nation appears poised to seek its own nuclear weapons in the near term. Several nations — including Italy, Belgium, Germany, and the Netherlands — currently host US warheads, but none are expressing any desire to develop independent nuclear capability. Germany, in particular, has long opposed the idea and even ended its civilian nuclear program after the Fukushima disaster in 2011. Other European nations that once ran secret nuclear programs, like Sweden, are not particularly likely to restart them, while Norwegian thinkers who advocated for a Nordic bomb have been rebuked by their own government in recent months.\n\nHowever, both Sweden and neighboring Finland have expressed openness to hosting nuclear weapons in the future — a posture that may represent the more likely path for European nations. Rather than new states creating their own arsenals, existing nuclear powers, particularly France, would be more likely to grow their stockpiles and extend their deterrent coverage.\n\nFrance under Emmanuel Macron has pushed hard to expand its nuclear umbrella in recent months. In a scenario where Poland and South Korea have been driven to develop the bomb, where US support is perceived as waning, and where norms against proliferation are eroding, France might be able — and indeed pressured — to expand its arsenal more readily. The European Union could find itself forced to view France's fewer than three hundred warheads as its primary nuclear deterrent, creating enormous pressure on Paris to scale up. Macron has drawn domestic criticism for suggesting France become a continent-wide nuclear guarantor, but such opposition might weaken considerably in a world where the nuclear order was shifting more broadly. Under present conditions, it would likely take France the better part of a decade to add just one hundred warheads to its arsenal, though greater investment could accelerate the process given that France already possesses all the requisite knowledge.\n\n## Saudi Arabia: The Petrostate Shuffle Begins\n\nMoving to the Middle East, a combination of an Iranian bomb, a Turkish bomb, and a pre-existing Israeli bomb could trigger what might be called the 'petrostate shuffle' — a dynamic in which highly ambitious, very wealthy nations with nuclear power initiatives already underway feel enormous pressure to respond in kind, simply to avoid being left out of a new regional arms race.\n\nThe most important nation to consider here is Saudi Arabia. Crown Prince Mohammed bin Salman has openly and repeatedly acknowledged since 2018 that Saudi Arabia intends to build a nuclear arsenal if Iran develops one — a warning he has refused to walk back despite international pressure. This suggests that Riyadh takes its own warning seriously and may already have contingency plans in place.\n\nSaudi officials have long sought coverage under America's nuclear umbrella but have resisted US attempts to impose standard anti-proliferation requirements, creating a situation where Saudi Arabia appears unlikely to settle for a US deterrent alone. The kingdom has been pursuing a nuclear program for years and is well on its way to bringing a reactor online. It has stockpiled nuclear ore for many years; according to The Guardian, Saudi Arabia in 2020 already had enough uranium ore to produce some ninety thousand tons of purified uranium. In 2023, the nation's Energy Minister revealed plans to develop a full nuclear cycle — producing yellowcake uranium, enriching it, and producing nuclear fuel that Saudi Arabia eventually plans to export.\n\nCritically, Saudi Arabia already possesses intercontinental ballistic missiles capable of mounting warheads, courtesy of China but reportedly with the sign-off of the American CIA. Under a Trump administration, it is not terribly likely that Saudi Arabia would face sanctions for pursuing the bomb in a world where Iran's nuclear program had gone operational. The kingdom would probably need international support to quickly develop elements of a weapons program it currently lacks, but it could solicit that support from either a friendly United States or a friendly China — and given the competitive dynamic between those two nations, both potential backers might be eager to agree. In a worst-case scenario, Saudi Arabia may need five years to get nuclear weapons operational, and possibly less.\n\n## The Cascade Effect: Why One Leads to Many\n\nThe central danger illuminated by this analysis is not any single nation's nuclear ambitions in isolation — it is the cascade effect. Each new nuclear-armed state fundamentally alters the security calculus of its neighbors and rivals, creating pressure for additional proliferation that existing treaties and diplomatic frameworks may be unable to contain.\n\nConsider the chain: Iran's breakout capability pressures Saudi Arabia and Turkey. Poland's pursuit of a deterrent gives Turkey justification within NATO and signals to the broader alliance that proliferation norms are weakening. South Korea's program validates the logic of independent deterrents for nations that feel abandoned by the United States, potentially influencing Japan and others in the Indo-Pacific. France expands its arsenal under pressure to compensate for a diminished American umbrella. Each link in the chain makes the next link more likely.\n\nThe treaties designed to prevent this — the Nuclear Nonproliferation Treaty, the Comprehensive Nuclear-Test-Ban Treaty, and various bilateral agreements — depend on a combination of great-power enforcement, security guarantees, and shared norms. When the guarantees become unreliable, the enforcement becomes selective, and the norms begin to erode, the entire architecture is at risk. Arms-control experts have long warned that the system is only as strong as its weakest link, and in early 2025, multiple links appear to be straining simultaneously.\n\n## Timelines and the Path to Twenty Nuclear Powers\n\nIf Poland, South Korea, and Iran all began confirmed efforts to build nuclear weapons — not necessarily producing finished products, but visibly traveling down that path — the resulting cascade could plausibly bring the world to twenty or more nuclear-armed states by 2040. The timelines vary considerably by nation: Iran could achieve breakout within months, South Korea within two to three years, Poland within five years at minimum, Turkey within three to ten years, and Saudi Arabia within roughly five years.\n\nThese timelines are not fixed; they depend on the level of international support or opposition each nation encounters, the degree to which existing alliances hold or fracture, and the willingness of established nuclear powers to either assist or obstruct new entrants. What makes the current moment uniquely dangerous is that many of the factors that historically restrained proliferation — reliable American security guarantees, strong nonproliferation norms, and great-power consensus against new nuclear states — are all weakening at the same time.\n\nThe world has lived with nine nuclear powers for years, and the balance, while precarious, has held. The prospect of twelve, fifteen, or twenty nuclear-armed states represents a fundamentally different kind of risk — not merely more of the same danger, but a qualitative transformation of the global security environment in which the probability of miscalculation, accident, or deliberate use rises with every new entrant to the nuclear club.\n\n## The United Arab Emirates: A Gold-Standard Agreement Under Strain\n\nFrom Saudi Arabia, the proliferation lens naturally shifts to its next-door neighbor, the United Arab Emirates. The UAE is generally considered one of the nations most resistant to its nuclear urges, owing in large part to a collaborative agreement with the United States that is widely regarded as the global gold standard for getting nations with civil nuclear programs to commit to avoiding weapons proliferation. But the UAE is already considerably more advanced on nuclear power than either Turkey or Saudi Arabia. As of 2024, the Emirates is operating all four reactors at its first nuclear power plant, with plans to build more.\n\nThe considerations here are fundamentally geopolitical. The UAE shares a growing rivalry with Saudi Arabia, with the two nations competing on an ever-larger scale each year. When it comes to international prestige and strategic leverage, there is no greater triumph than procuring a nuclear weapon. For the UAE to sit quietly by while Saudi Arabia, Turkey, and Iran all acquire nuclear weapons is not a likely scenario. While the nation's gold-standard agreement with the United States would almost certainly preclude an Emirati bomb in today's world, the hypothetical under discussion is not today's world — it is a world where the international nuclear order is already breaking down rapidly, and where today's approach to arms control has been turned on its head.\n\nThe UAE is one of those nations with a nuclear program currently understood to be proliferation-proof. But if the Emirates were to start down the path to a bomb, the timeline would likely resemble Turkey's: perhaps as few as three years, perhaps as many as ten — but with the potential added benefit of assistance from nations looking to spite the Saudis on their own doorstep. Other petrostates worthy of consideration include Qatar and Azerbaijan, although neither nation appears to be in a position to start a nuclear weapons program anytime soon.\n\n## Egypt: A Rising Power With a Nuclear Past\n\nMoving to North Africa, Egypt — itself a neighbor to Saudi Arabia in all but the most pedantic technicalities — is another rising power that deserves serious consideration. After years on ice, Egypt restarted its nuclear power program in 2013, and that program is now well underway as the nation builds the El-Dabaa Nuclear Power Plant on the Mediterranean coast. The Russian-backed initiative should yield a functioning reactor within the next decade, and Israel has expressed interest in a second reactor as well.\n\nEgypt is another nation with nuclear weapons in its past, and it has conducted experimentation into other weapons of mass destruction, working toward offensive biological weapons and deploying chemical weapons in the 1960s. The nation possesses ample delivery mechanisms for a nuclear weapon, and prominent ex-military officials have suggested that in a world where Iran obtains nuclear weapons — and especially if Turkey and Saudi Arabia follow — Egypt would be forced to procure weapons of its own.\n\nBut even if the threat of a nuclear Middle East were not enough to prompt an Egyptian bomb, a nuclear Ethiopia almost certainly would be. Egypt and Ethiopia are cultivating an emerging and bitter rivalry in northern Africa, at a time when Ethiopia under its autocrat Abiy Ahmed is working hard to become a regional power somewhere between Erdogan and Kim Jong-un on the unpredictability spectrum. Ethiopia has considerable leverage over Egypt by way of its ability to control the flow of the Nile River, while Egypt is rapidly aligning itself with other nations concerned about Ethiopia's disruptive potential. Both Egypt and Ethiopia could potentially develop nuclear weapons within a decade if they secured the right international support — or perhaps within fifteen years under more conservative estimates.\n\n## Ethiopia and Eritrea: Africa's Unlikely Nuclear Contenders\n\nEthiopia's inclusion on any list of potential nuclear proliferators may seem surprising, but the nation's trajectory under Abiy Ahmed makes it a genuine consideration in a cascading scenario. Ahmed asked France to station nuclear missiles on Ethiopian territory as far back as 2019, and the nation is working on a civilian nuclear power program via cooperation with Russia. Ethiopia, along with most of Africa, has long advocated the preservation of the continent as a nuclear-weapons-free zone, but if there is any leader likely to abandon those pledges at a time when nuclear proliferation is ongoing, it is Abiy Ahmed.\n\nEthiopia would probably take quite a while to develop nuclear weapons on its own, if it could ever get there at all. However, in a world where the Middle East is already going nuclear and the old order of nonproliferation is breaking down fast, Ahmed's broader desire to turn Ethiopia into a regional power — combined with his proven tendency to disregard international rules and norms — could make a push to develop a nuclear warhead a realistic possibility. Support from any number of actors, from the UAE to Russia, might be forthcoming as well.\n\nPerhaps most unexpectedly, if Ethiopia were to go nuclear, one other nation would start to look at the bomb: Eritrea. Outwardly, a state in such obvious internal shambles as Eritrea would not be a likely candidate to build a nuclear weapon or even come close. The trouble, however, is the closeness between a nation often referred to as 'the North Korea of Africa' and the actual nation of North Korea. Eritrea shares ties with North Korea, and the two nations have even engaged in under-the-table military collaboration. In a world where even Ethiopia is looking at acquiring warheads, Eritrea would be under real pressure to at least try asking North Korea for support — either to station North Korean warheads as a deterrent or to help Eritrea develop its own program, similar to the circumstances under which North Korea accelerated its own program in the early 2000s. Given the chance for North Korea to both profit from selling nuclear secrets and to start building a sphere of influence a whole continent away, it is not necessarily assured that Pyongyang would refuse.\n\n## Japan: The World's Most Nuclear-Ready Non-Nuclear State\n\nIf South Korea were to begin a nuclear weapons program, it is all but assured that North Korea would step up its own efforts to the extent it is able. But it is the threat of a potentially more aggressive, more belligerent North Korea that draws in the nation of Japan.\n\nIt should be no surprise that Japan, as the only nation ever to have nuclear weapons used against it, is not particularly friendly to the idea of a nuclear program of its own. But at the same time, Japan is easily the world's nation with the most firmly established latent capability to produce nuclear weapons if it ever needed to. Japan abandoned its goal to phase out nuclear power after the 2011 Fukushima disaster and is now working to increase its reliance on civilian nuclear energy, with the intent of supplying a fifth of the nation's electricity that way by 2030. As a result of its long-running nuclear power program, Japan is in possession of a substantial quantity of weapons-grade plutonium — enough to create well over five thousand nuclear bombs through that method alone, without even accounting for the enriched uranium in Japan's possession.\n\nJapan has become the only nation in the world that possesses a full nuclear fuel cycle without nuclear weapons, and it has robust delivery mechanisms for a warhead if it ever decided to make one. The nation has innumerable nuclear scientists of its own, plus an exceptionally close relationship with the United States, to the point that a Japanese effort to build a warhead might even enjoy direct American support under the right circumstances.\n\nThe nation's current prime minister has called for Japan to consider sharing US nuclear weapons on its soil, and former Prime Minister Shinzo Abe brought nuclear weapons back into the national discourse after decades of treating them as taboo following Hiroshima and Nagasaki. While the Japanese public is not currently in favor of acquiring a nuclear bomb, it may face a situation similar to South Korea's, where changing international circumstances drive the public to change their minds. If South Korea believes it must develop a bomb — probably because of signs of waning US support that Japan would observe too — then the likely outcomes, from North Korean aggression to broader regional destabilization and a potential invasion of Taiwan, would push Japan to act quickly. Although there is no concrete timeline for Japan to produce a warhead if it began work today, a conservative estimate places the latency period at just six months — and under the right circumstances, it could accomplish the task in a mere fraction of that time.\n\n## Australia: A Shifting Nuclear Calculus in the Pacific\n\nLess likely to take the plunge but not entirely unlikely is Australia, where public opinion on nuclear matters has shifted rapidly in recent years. From a nation long hesitant to engage with anything even remotely nuclear-shaped, Australia now appears as if it may construct reactors at no fewer than seven sites nationwide, should the leader of Australia's opposition, Peter Dutton, be elected to office. The nation is also developing nuclear-powered submarines with American and British support, and it hosts a full one-third of the world's uranium deposits.\n\nAustralia previously formed a plan to develop plutonium for nuclear weapons production during the Cold War. Today, almost two-thirds of Australians support both the adoption of nuclear power and the adoption of nuclear submarines — both figures vastly increased from prior decades. Perhaps most tellingly, thirty-six percent of Australians supported acquiring nuclear weapons in 2022, as opposed to just twenty percent in 2010. Developments abroad may well prompt the Australian public to shift its position further.\n\nIn a world where the United States may begin to pull back from its international partnerships, it is Australia alongside Japan and South Korea that would form a bulwark against Chinese ambitions in the Pacific. While Australia would not be likely to pursue nuclear weapons tomorrow, in a nuclear cascade scenario — particularly one in which Australia would risk being left behind as its regional partners arm themselves — the calculus could change dramatically.\n\n## Germany: Europe's Reluctant Last Domino\n\nIf Japan were to utilize its breakout potential and produce a nuclear bomb, the ripple effects would extend all the way back to continental Europe, where Germany would emerge as one more contender. As previously noted, Germany is a nation where the United States currently stations warheads, but it has been deeply reticent to develop its own nuclear weapons program for a very long time. A large part of Germany's hesitance has actually come from following Japan's lead. As the two nations that led the losing coalition in the most devastating war in human history, Japan and Germany have made it a point to avoid seeking out weapons of mass destruction. Germany even swore off its civil nuclear program after the Fukushima disaster of 2011 — even after Japan reversed course on its own deactivation initiative.\n\nYet as in so many other nations, the German public is slowly reversing course on nuclear weapons. A 2022 poll found for the first time in decades that a majority of the public approved of the presence of US nuclear weapons in Germany. The country's former leader, Olaf Scholz, spent a fair portion of his time pushing against nuclearization talk in Germany, but Scholz has been voted out, and his successor, Friedrich Merz, is pushing for weapons-sharing agreements with Britain and France.\n\nGermany has the technical capabilities to invest in a nuclear program if it wished to. Although the nation still does not seem inclined to build those weapons today, the combination of a new nuclear neighbor in Poland, plus a tacit or even explicit expression of support from a nuclearizing Japan, could be enough to push Germany over the edge. If the nation were to reverse course — unlikely as that may be — it may not take very long to go operational, given its technical knowledge, military assets, and likely support from several allied nations.\n\n## The Speed of Collapse: Why the Cascade Could Unfold Faster Than Expected\n\nOne of the most critical and underappreciated dimensions of a nuclear cascade is how fast it could unfold. The timelines discussed throughout this analysis — months for Iran, two to three years for South Korea, five years for Poland, and so on — assume that each nation begins its program in sequence, responding only after a predecessor has completed its first warhead. In reality, nations that know or even suspect that their adversaries are building a bomb have no incentive to wait until there is proof of detonation before responding.\n\nNations might try to delay because of the fear of repercussions from the international order, but that is precisely the order that is falling apart. If nations feel at liberty to start their own nuclear programs as soon as their adversaries do the same, then a cascade would not necessarily take years to play out. A particularly catastrophic six-week stretch of diplomatic breakdown could be enough to set the entire chain in motion — and the world has experienced several such stretches in recent memory.\n\nThis acceleration dynamic means that the window for intervention is far narrower than it might appear. By the time the international community recognizes that a cascade is underway, multiple nations may already be well down the path to weaponization, making diplomatic reversal exponentially more difficult with each passing week.\n\n## Deterrents Against the Cascade: What Could Still Prevent It\n\nFor all the alarm warranted by the current trajectory, there are significant protections that may prevent even the start of this cascade from coming to pass. Iran is under severe international pressure, including the threat of a US bombing campaign, and hardliners in Washington have indicated that, at least on paper, they are willing to deliver considerable force to prevent Iran from acquiring the bomb. South Korea and Poland, if they chose to pursue nuclear programs, could each face intense backlash from their allies — Poland potentially ostracized from NATO and sanctioned heavily by the European Union, South Korea stranded on its own against North Korea and China on its doorstep.\n\nAdversaries, too, serve as deterrents. China or Russia would be just as likely to attempt pre-emptive action against South Korea and Poland, respectively, as the United States would be against Iran. All those deterrents, stacked on top of one another, could be enough to stop each nation from taking the leap — and the same is true for every other potential proliferator discussed in this analysis.\n\nYet the broader geopolitical environment complicates even these protections. Long regarded as the guarantor of global security, the so-called 'rules-based international order' risks becoming a thing of the past, as superpowers, regional powers, minor powers, and tiny nations alike push ever harder against boundaries that international norms were supposed to enforce. From Russia's incursion into Ukraine, to China's potential invasion of Taiwan, to America's potential abandonment of its allies abroad, those constraints are growing weaker by the day. The expectation that countries do not pursue nuclear weapons has been rock-solid for decades — but not anymore. And if that global rule is up for debate, then confidence in the rule above the rule — the global standard that calls for nations to stand together in opposition when a country goes rogue and pursues the bomb — becomes equally uncertain. If that falls apart, then it takes only one nuclear-armed nation supporting allies in their nuclear ambitions for the world to descend into a proliferation race.\n\n## Rational Actors, Irrational Outcomes: The Paradox at the Heart of Proliferation\n\nPerhaps the most unsettling dimension of the nuclear cascade scenario is that it does not require a single irrational actor to unfold. Every nation discussed in this analysis — from Poland to South Korea to Iran to Saudi Arabia to Japan to Germany — has its own clear set of incentives to take the leap. Nowhere in the chain does there have to be an absolutely mad dictator determined to follow a ludicrous path to its worst conclusion. Instead, the cascade consists of rational nations forming rational responses to other rational nations, all of whom can thoroughly justify the part they individually play in a chain reaction that is bigger than any of them.\n\nIf an era of sudden nuclear proliferation is going to come from anything, it will come from this: a moment in history when several nations, perhaps even a dozen or more, each pivot to address new challenges from the world around them. Each nation takes a series of steps that it believes will protect its interests, its sovereignty, and its place on the world stage, as any nation would. Then, at the logical conclusion of each of those series of steps, those nations find a nuclear warhead.\n\nIn Poland, in South Korea, and to an extent even in Iran, that is precisely what is happening now. Donald Tusk, Han Duck-soo and his likely successor Lee Jae-myung, even the Ayatollah Ali Khamenei — they are not stupid, and they are not insane. They are marching down the path to a nuclear bomb because that is what they believe would make sense. And it is in a world where nuclear proliferation makes sense that the entire world needs to prepare for what comes next.\n\n## A More Likely Outcome: Not Twenty, But How Many?\n\nThe worst-case scenario outlined in this analysis — a world with twenty or more nuclear-armed states by 2040 — represents a full breakdown of the post-World War II nuclear order, a complete abandonment of the modern rules of nonproliferation that govern today's world. In such a world, perhaps not all the nations discussed would ultimately take the leap — but perhaps others would, like Brazil, Canada, Italy, or others not yet on anyone's radar.\n\nThe odds of the full worst-case scenario remain slim. But the purpose of tracing the cascade to its logical extreme is not to predict the future with certainty — it is to illustrate the grave importance of the nuclear conversations happening today. From Poland to South Korea to Iran, there are real and ongoing discussions about whether to develop an operational nuclear capability. Even if the outcome is not the full worst-case scenario, it could very well be a sequence of repercussions in which significant parts of this cascade do play out. There are a great many outcomes less catastrophic than twenty nuclear powers that still manage to be very bad in their own right.\n\nThe world has nine nuclear nations today, and it may not have twenty by 2040. But how certain can anyone be that the world will not have twelve? How certain can anyone be that it will not have fifteen? By examining the full scope of the cascade — from the first domino to the last — policymakers and publics alike can better understand the risk of even a partial proliferation spiral, and the urgency of acting before the chain reaction begins.\n\n## Related Coverage\n- [The UAE is Destabilizing the Entire Middle East](https://warfronts.pub/conflicts/the-uae-is-destabilizing-the-entire-middle-east)\n- [The UAE's Regional Ambitions Collapse as Middle East Powers Push Back](https://warfronts.pub/geopolitics/uae-regional-ambitions-collapse-middle-east-pushback)\n- [How the UAE's Regional Meddling Triggered a Historic Realignment Across the Middle East](https://warfronts.pub/geopolitics/uae-destabilizing-middle-east-regional-realignment-2026)\n\n## FAQ\n\n### How soon could Poland realistically acquire nuclear weapons?\n\nPoland faces significant hurdles and would need at least five years to develop nuclear weapons, with 2030 representing the absolute floor for a realistic Polish nuclear capability. The nation currently has no civilian nuclear power installations, with its first reactors not expected until after 2030, and lacks the institutional knowledge from running a prior nuclear weapons program. There is a possibility that France, the United States, South Korea, or another ally could offer support through a joint program or framework of mutual assistance.\n\n### What is a nuclear cascade and why is it so dangerous?\n\nA nuclear cascade is a chain reaction of proliferation in which one nation's decision to acquire nuclear weapons triggers others to do the same, creating a self-reinforcing spiral. Each new nuclear-armed state fundamentally alters the security calculus of its neighbors and rivals, creating pressure for additional proliferation. The danger is that this represents a qualitative transformation of the global security environment, where the probability of miscalculation, accident, or deliberate use rises with every new entrant to the nuclear club.\n\n### Which countries would most likely follow if Poland, South Korea, and Iran go nuclear?\n\nTurkey would be a prime candidate within NATO if Poland pursues nuclear weapons, having hinted at developing the bomb since 2019. Saudi Arabia has openly stated it will build a nuclear arsenal if Iran develops one. Japan, with its massive plutonium stockpile, could respond to a South Korean program within six months. Other potential proliferators include the UAE, Egypt, Ethiopia, Australia, and potentially Germany if Japan were to go nuclear.\n\n### How quickly could Japan develop a nuclear weapon if it decided to?\n\nJapan exists in a state of extremely high nuclear latency and could produce a functional warhead within six months under conservative estimates, and potentially in a fraction of that time under the right circumstances. Japan possesses enough weapons-grade plutonium to create well over five thousand nuclear bombs, has a full nuclear fuel cycle, robust delivery mechanisms, innumerable nuclear scientists, and an exceptionally close relationship with the United States that might even provide direct support.\n\n### What role does uncertainty about US security commitments play in nuclear proliferation?\n\nErosion of confidence in the American nuclear umbrella is a structural driver of proliferation. Donald Trump's second term has generated widespread concern among US allies about whether Washington will honor its commitments to defend other nations in times of war. This ambiguity pushes nations to consider managing their own defense independently. When allied nations can no longer trust that the world's largest nuclear power will come to their defense, the incentive to develop independent deterrents becomes overwhelming.\n\n## Sources\n- <https://www.politico.eu/article/donald-tusk-plan-train-poland-men-military-service-russia/>\n- <https://www.nytimes.com/2025/03/07/world/europe/poland-nuclear-trump-tusk.html>\n- <https://www.cbsnews.com/news/poland-president-duda-us-nuclear-weapons-deploy/>\n- <https://www.iiss.org/publications/strategic-comments/2023/polands-bid-to-participate-in-nato-nuclear-sharing/>\n- <https://www.atlanticcouncil.org/blogs/new-atlanticist/why-polands-president-wants-us-nuclear-weapons/>\n- <https://breakingdefense.com/2025/03/a-nuclear-poland-logistics-political-challenges-ahead-of-potential-warsaw-deal/>\n- <https://www.euronews.com/2025/03/21/could-another-european-country-develop-its-own-nuclear-weapons>\n- <https://ip-quarterly.com/en/future-zeitenwende-scenario-5-poland-becomes-nuclear-power>\n- <https://world-nuclear.org/information-library/country-profiles/countries-o-s/poland>\n- <https://foreignpolicy.com/2024/09/22/south-korea-nuclear-weapons-proliferation-deterrence-strategy/>\n- <https://www.nytimes.com/2024/08/17/world/asia/south-korea-nuclear-arsenal.html>\n- <https://www.cato.org/commentary/why-south-korea-wants-nuclear-weapons-now-more-ever>\n- <https://www.foreignaffairs.com/north-korea/why-south-korea-should-go-nuclear-kelly-kim>\n- <https://theconversation.com/nuclear-war-threat-why-africas-pushing-for-a-complete-ban-253171>\n- <https://warontherocks.com/2024/09/south-koreas-nuclear-latency-dilemma/>\n- <https://carnegieendowment.org/research/2024/03/playing-with-proliferation-how-south-korea-and-saudi-arabia-leverage-the-prospect-of-going-nuclear?lang=en>\n- <https://www.orfonline.org/expert-speak/south-korea-s-quest-for-nuclear-weapons>\n- <https://www.reuters.com/world/trump-says-there-will-be-bombing-if-iran-does-not-make-nuclear-deal-2025-03-30/>\n- <https://www.cfr.org/article/what-are-irans-nuclear-and-missile-capabilities>\n- <https://apnews.com/article/iran-nuclear-iaea-weapons-grade-uranium-trump-0b11a99a7364f9a43e1c83b220114d45>\n- <https://thebulletin.org/2025/01/how-quickly-could-iran-build-its-first-nuclear-weapon-look-at-china/#:~:text=Some%20nuclear%20experts%20argue%20it,as%20three%20to%20five%20weeks>\n- <https://isis-online.org/isis-reports/detail/how-quickly-could-iran-make-nuclear-weapons-today/8>\n- <https://foreignpolicy.com/2024/10/10/iran-nuclear-weapon-warhead-missile-how-soon/>\n- <https://nordicmonitor.com/2024/09/turkey-needs-to-acquire-nuclear-arms-to-stop-israel-urges-erdogans-chief-fatwa-giver/>\n- <https://www.iar-gwu.org/blog/erdogans-nuclear-itchstrong-strongwhy-turkeys-nuclear-program-is-a-threat-to-regional-stability-and-the-international-nonproliferation-regime>\n- <https://www.brookings.edu/articles/its-time-to-get-us-nukes-out-of-turkey/>\n- <https://www.fdd.org/in_the_news/2025/02/05/faq-is-turkey-the-next-nuclear-proliferant-state/>\n- <https://www.armscontrol.org/act/2019-10/news/turkey-shows-nuclear-weapons-interest>\n- <https://www.reuters.com/article/world/erdogan-says-its-unacceptable-that-turkey-cant-have-nuclear-weapons-idUSKCN1VP2Q8/>\n- <https://thebulletin.org/2024/12/the-rise-and-fall-of-swedens-nuclear-disarmament-advocacy/>\n- <https://www.icanw.org/sweden_nato_and_the_irresponsible_calls_for_more_nuclear_sharing_in_europe>\n- <https://www.bbc.com/future/article/20240412-the-secret-scandinavian-a-bomb-project>\n- <https://www.politico.com/news/magazine/2024/07/04/europe-us-nuclear-weapons-00166070>\n- <https://www.reuters.com/world/europe/how-realistic-is-frances-offer-extend-its-nuclear-umbrella-2025-03-06/>\n- <https://warontherocks.com/2025/03/eurodeterrent-a-vision-for-an-anglo-french-nuclear-force/>\n- <https://www.aftenposten.no/meninger/debatt/i/pPEOxj/norden-har-teknologien-og-pengene-til-aa-skaffe-seg-atomvaapen>\n- <https://www.icanw.org/saudi_arabia>\n- <https://www.nti.org/countries/saudi-arabia/>\n- <https://georgetownsecuritystudiesreview.org/2024/12/18/the-nuclear-kingdom-accessing-saudi-arabias-nuclear-behavior/>\n- <https://www.unav.edu/web/global-affairs/in-pursuit-of-the-bomb-is-saudi-arabia-playing-the-nuclear-game->\n- <https://www.armscontrol.org/act/2023-11/news/saudi-push-enrichment-raises-concerns>\n- <https://www.theguardian.com/world/2023/sep/21/crown-prince-confirms-saudi-arabia-seek-nuclear-arsenal-iran-develops-one>\n- <https://foreignpolicy.com/2024/01/25/the-hidden-rivalry-of-saudi-arabia-and-the-uae/>\n- <https://arabcenterdc.org/resource/the-uae-saudi-arabia-rivalry-becomes-a-rift/>\n- <https://epicenter.wcfia.harvard.edu/blog/allies-odds-tracking-rivalry-between-saudi-arabia-and-united-arab-emirates>\n- <https://world-nuclear.org/information-library/country-profiles/countries-a-f/egypt>\n- <https://www.memri.org/tv/egypt-military-analyst-gen-samir-farag-if-iran-gets-nukes-we-want-them-too>\n- <https://www.nti.org/countries/egypt/>\n- <https://nucleus.iaea.org/sites/INPRO/df22/Day%203/3.2.Ethiopia.pdf>\n- <https://www.thereporterethiopia.com/37427/>\n\n<!-- youtube:wBw71Aao0SM -->"
url: https://warfronts.pub/article/nuclear-cascade-twenty-nuclear-powers-by-2040.md
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  - name: Simon Whistler
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---

<!-- aeo:section start="lede" -->
Mutually assured destruction has kept the global order intact since the dawn of the nuclear age — a grim but effective equilibrium among nine nuclear-armed states. Yet in early 2025, that equilibrium is showing unmistakable signs of strain. Poland's prime minister has publicly called for his nation to pursue nuclear capabilities, South Korea's defense establishment is treating a homegrown deterrent as a serious policy option, and Iran is believed to be mere weeks of enrichment away from weapons-grade uranium. Arms-control experts warn that if even one of these nations crosses the threshold, a nuclear cascade could follow — a chain reaction of proliferation in which state after state races to acquire the bomb. The result, in a worst-case but increasingly plausible scenario, could be a world with twenty or more nuclear powers before 2040.

<!-- aeo:section end="lede" -->
<!-- aeo:section start="key-takeaways" -->
## Key Takeaways
- Poland, South Korea, and Iran are the three most immediate candidates for nuclear acquisition, each with varying timelines but all potentially capable of producing warheads by or before 2030.
- A major driver behind Polish and South Korean interest is eroding confidence in the United States' willingness to honor its security commitments under the Trump administration, pushing allies to consider independent deterrents.
- A nuclear cascade — in which one nation's decision to proliferate triggers others — is the central fear of arms-control experts, and the current geopolitical environment makes such a cascade more plausible than at any point since the Cold War.
- Turkey, Saudi Arabia, and potentially other Middle Eastern and NATO states could follow suit if Iran, Poland, or South Korea cross the nuclear threshold, dramatically expanding the number of nuclear-armed nations.
- Existing treaties like the Nuclear Nonproliferation Treaty and the Comprehensive Nuclear-Test-Ban Treaty may prove insufficient to prevent cascading proliferation if major signatories begin defecting from their commitments.

<!-- aeo:section end="key-takeaways" -->
<!-- aeo:section start="the-current-nuclear-order-and-why-it-s-under-pressure" -->
## The Current Nuclear Order and Why It's Under Pressure

The existing global nuclear architecture rests on a deceptively simple premise: if anyone uses the bomb, everyone uses the bomb. Nine nations — the United States, Russia, China, France, the United Kingdom, India, Pakistan, Israel, and North Korea — currently possess nuclear weapons, and each exists in a deadly serious balance with the others. Russia's use would trigger responses from France and Britain; Pakistan's from India; America's from China and North Korea. This web of mutually assured destruction has held since 1945, but it depends on a relatively small and stable number of actors.

What makes the present moment so dangerous is that a growing number of nations outside this club are actively exploring the nuclear option. Iran is reportedly days away from weapons-grade enrichment capability. South Korea is giving serious institutional consideration to a homegrown deterrent. Poland's leadership has made historically bold public statements about pursuing nuclear capabilities. Each of these developments is alarming in isolation, but the real nightmare scenario is a nuclear cascade — one new entrant prompts another, which prompts another, in a self-reinforcing spiral of proliferation that existing treaties and agreements may be powerless to stop.

<!-- aeo:section end="the-current-nuclear-order-and-why-it-s-under-pressure" -->
<!-- aeo:section start="poland-europe-s-aspiring-nuclear-power" -->
## Poland: Europe's Aspiring Nuclear Power

In early March 2025, Polish Prime Minister Donald Tusk made history with an address to parliament in which he called for Poland to build an army five hundred thousand strong and, crucially, to avoid restricting itself to conventional weapons. 'We must be aware that Poland must reach for the most modern capabilities also related to nuclear weapons and modern unconventional weapons,' Tusk declared. 'This is a race for security, not for war.'

Tusk explicitly invoked Ukraine's decision to surrender its nuclear arsenal after the Cold War and the devastating consequences that followed at Russia's hands. The parallel is stark: Poland itself hosted Soviet nuclear weapons during the Cold War, but those weapons were removed in 1991. For a nation with deep cultural memory of occupation by Soviets, Nazis, and other powers, the lesson of Ukraine's vulnerability has landed with particular force.

Since Tusk's address, Poland has confirmed its interest in acquiring a nuclear deterrent on its own soil, calling for the United States to deploy nuclear weapons to Poland and deepening conversations with France to the same effect. Yet the option of developing Poland's own warheads remains on the table should allies fail to deliver. Public sentiment supports this trajectory: in February 2025, nearly fifty-three percent of Poles supported the idea of their country acquiring its own nuclear weapons.

Logistically, however, Poland faces significant hurdles. The nation currently has no civilian nuclear power installations, with its first reactors not expected until sometime after 2030. Nor does Poland possess the institutional knowledge that comes with having run a prior nuclear weapons program — it hosted Soviet bombs but never built them. Even on the most aggressive possible timeline, nuclear weapons for Poland are probably at least five years away. There is a slight possibility that France, the United States, South Korea (with whom Poland is building an increasingly close relationship), or another ally could offer support through a joint program or framework of mutual assistance. But 2030 represents the absolute floor for a realistic Polish nuclear capability.

<!-- aeo:section end="poland-europe-s-aspiring-nuclear-power" -->
<!-- aeo:section start="south-korea-high-nuclear-latency-and-growing-resolve" -->
## South Korea: High Nuclear Latency and Growing Resolve

South Korea's interest in a homegrown nuclear deterrent has been circulating in public discourse longer than Poland's. In September 2024, then-Defense Minister Kim Yong-hyun raised the possibility during his confirmation hearings, arguing that South Korea should treat nuclear weapons acquisition as a serious option in response to North Korea's nuclear threat. Kim's statement was the latest in a long series of similar remarks by South Korean leaders, all reflecting a growing willingness to pursue an independent deterrent — both to counter Pyongyang and to gain leverage with Washington.

Since January 2025, interest within South Korea has only intensified as demands from Washington prompt experts and policymakers to give the idea serious thought. Public opinion strongly favors the move: a 2024 poll indicated that as much as seventy-six percent of South Koreans would support their country developing its own nuclear weapons. A second poll, summarized in a 2024 Center for Strategic and International Studies report, found support below forty percent — but critically, over half of those opposed said they would change their stance if they became concerned that the United States might renege on its security pledges.

From a logistical standpoint, South Korea is far better positioned than Poland. The country exists in a state of high nuclear latency, meaning it possesses the requisite technology, expertise, and state infrastructure to build a bomb if the decision were made. South Korea operated a nuclear weapons program through the 1980s and is among the world's most prolific users of civilian nuclear energy, having built itself into a nuclear reactor exporter. By most estimates, South Korea could produce its first functional warhead within two to three years, though that timeline represents the absolute minimum needed to produce bomb-grade fissile materials. Unlike Japan, which already has over forty-five tons of bomb-grade plutonium set aside, South Korea would need to enrich nuclear material to weapons-grade levels — a process that, while achievable, adds time to the clock.

<!-- aeo:section end="south-korea-high-nuclear-latency-and-growing-resolve" -->
<!-- aeo:section start="iran-days-away-from-weapons-grade-uranium" -->
## Iran: Days Away from Weapons-Grade Uranium

On the opposite side of the world's geopolitical divides sits Iran, believed to have nuclear breakout capability as of early 2025. According to recent estimates, Iran has accelerated its production of near-weapons-grade uranium — enriching it not quite to the point of weapons-grade, but to a level where only a couple of weeks of additional enrichment would be required to cross that threshold.

Having weapons-grade uranium, of course, is not the same as having a nuclear bomb. It would take Iran more than a couple of weeks to actually construct a working weapon and integrate a warhead onto a delivery system capable of reaching an enemy target. But even that full capability is estimated to be only a few months away from the moment Iran decides to shift from its current posture to an all-out push. More conservative estimates place the timeline at up to two years. Once a warhead is assembled, Iran already possesses nuclear-capable missiles; the remaining challenge is integration and deployment.

Iran's proximity to breakout capability makes it arguably the most immediate proliferation concern among the three leading candidates. Its progress also serves as a powerful catalyst for other nations in the region — particularly Saudi Arabia and Turkey — to accelerate their own nuclear ambitions.

<!-- aeo:section end="iran-days-away-from-weapons-grade-uranium" -->
<!-- aeo:section start="the-role-of-american-uncertainty" -->
## The Role of American Uncertainty

A common thread running through the nuclear ambitions of Poland, South Korea, and other allied nations is deep uncertainty about the reliability of the United States as a security guarantor. Donald Trump's second term as president has generated widespread concern among US allies, from NATO nations to Taiwan and beyond. These allies fear that Washington under Trump either might not honor its commitments to defend other nations in times of war, or at the very least will refuse to make firm pledges until a crisis actually arrives.

Regardless of what Trump and his inner circle would ultimately choose in a genuine moment of crisis, the ambiguity itself is corrosive. It is pushing nations to think carefully about managing their own defense independently. France and Britain have demonstrated interest in coalition-building without the US. Canada and others are working to reduce dependence on American weapons systems. Poland and South Korea, both rapidly militarizing nations that consider themselves on the front lines of future conflicts — South Korea anticipating confrontation with the North and China, Poland expecting to serve as NATO's primary battlefield in a war with Russia — see a nuclear deterrent as a potentially invaluable tool for demonstrating that they are simply not to be challenged.

This erosion of confidence in the American nuclear umbrella is not merely a political inconvenience; it is a structural driver of proliferation. When allied nations can no longer trust that the world's largest nuclear power will come to their defense, the incentive to develop independent deterrents becomes overwhelming — and the treaties designed to prevent proliferation lose their most powerful enforcement mechanism.

<!-- aeo:section end="the-role-of-american-uncertainty" -->
<!-- aeo:section start="turkey-nato-s-wild-card" -->
## Turkey: NATO's Wild Card

If Poland were to begin working toward nuclear weapons development, one NATO member stands out as a prime candidate to follow suit: Turkey. President Erdogan has hinted at developing the bomb for more than half a decade. In 2019, during a broader dispute with the United States, Erdogan explicitly pushed back against prohibitions keeping Turkey non-nuclear: 'Some countries have missiles with nuclear warheads, not one or two. But we can't have them. This, I cannot accept. There is no developed nation in the world that doesn't have them.'

Erdogan has been laying the groundwork for Turkey to develop a deterrent comparable to Israel's. Turkey currently hosts American nuclear warheads and is a signatory to both the Nuclear Nonproliferation Treaty and the Comprehensive Nuclear-Test-Ban Treaty — though, like other nations under discussion, Turkey has not historically been inclined to act against its perceived interests simply to honor international agreements.

Turkey's first civilian nuclear plant is expected to supply up to a tenth of the nation's energy needs, with additional reactors planned. While experts describe the first reactor as 'proliferation-resistant,' it can serve as a valuable experiential teaching tool for Turkish nuclear physicists, making the process of developing a weapon somewhat easier over time. Meanwhile, Turkey appears to be working surreptitiously toward weaponization, reportedly securing mining rights to access uranium in Niger in 2024. The idea of a Turkish bomb has also gained strength among Erdogan's nationalist supporters and is becoming increasingly normalized in Turkish culture.

In a world where both Poland and Iran are moving toward nuclear weapons, Turkey would likely lose any remaining interest in restraint. A nuclearizing Poland would give Ankara justification to approach alliance members and argue that if the Poles can build a bomb, Turkey should be permitted to do the same. A nuclear Iran would be an even more powerful motivator — if both Iran and Israel were nuclear-armed, it would be extremely difficult to argue that Turkey should refrain from matching them.

Pakistan, as part of an emerging strategic alliance with Turkey long suspected to include a nuclear dimension, might even be willing to grant Turkey direct support. As for a timeline, Turkey's path is harder to estimate than other nations due to the proliferation-resistant nature of its current program. Turkey would still need considerable time to enrich weapons-grade uranium, learn to construct an actual warhead, and integrate it onto a delivery system. A rough estimate places Turkey's timeline at longer than three years but less than ten.

<!-- aeo:section end="turkey-nato-s-wild-card" -->
<!-- aeo:section start="the-rest-of-europe-expansion-rather-than-proliferation" -->
## The Rest of Europe: Expansion Rather Than Proliferation

Beyond Poland and Turkey, no other European nation appears poised to seek its own nuclear weapons in the near term. Several nations — including Italy, Belgium, Germany, and the Netherlands — currently host US warheads, but none are expressing any desire to develop independent nuclear capability. Germany, in particular, has long opposed the idea and even ended its civilian nuclear program after the Fukushima disaster in 2011. Other European nations that once ran secret nuclear programs, like Sweden, are not particularly likely to restart them, while Norwegian thinkers who advocated for a Nordic bomb have been rebuked by their own government in recent months.

However, both Sweden and neighboring Finland have expressed openness to hosting nuclear weapons in the future — a posture that may represent the more likely path for European nations. Rather than new states creating their own arsenals, existing nuclear powers, particularly France, would be more likely to grow their stockpiles and extend their deterrent coverage.

France under Emmanuel Macron has pushed hard to expand its nuclear umbrella in recent months. In a scenario where Poland and South Korea have been driven to develop the bomb, where US support is perceived as waning, and where norms against proliferation are eroding, France might be able — and indeed pressured — to expand its arsenal more readily. The European Union could find itself forced to view France's fewer than three hundred warheads as its primary nuclear deterrent, creating enormous pressure on Paris to scale up. Macron has drawn domestic criticism for suggesting France become a continent-wide nuclear guarantor, but such opposition might weaken considerably in a world where the nuclear order was shifting more broadly. Under present conditions, it would likely take France the better part of a decade to add just one hundred warheads to its arsenal, though greater investment could accelerate the process given that France already possesses all the requisite knowledge.

<!-- aeo:section end="the-rest-of-europe-expansion-rather-than-proliferation" -->
<!-- aeo:section start="saudi-arabia-the-petrostate-shuffle-begins" -->
## Saudi Arabia: The Petrostate Shuffle Begins

Moving to the Middle East, a combination of an Iranian bomb, a Turkish bomb, and a pre-existing Israeli bomb could trigger what might be called the 'petrostate shuffle' — a dynamic in which highly ambitious, very wealthy nations with nuclear power initiatives already underway feel enormous pressure to respond in kind, simply to avoid being left out of a new regional arms race.

The most important nation to consider here is Saudi Arabia. Crown Prince Mohammed bin Salman has openly and repeatedly acknowledged since 2018 that Saudi Arabia intends to build a nuclear arsenal if Iran develops one — a warning he has refused to walk back despite international pressure. This suggests that Riyadh takes its own warning seriously and may already have contingency plans in place.

Saudi officials have long sought coverage under America's nuclear umbrella but have resisted US attempts to impose standard anti-proliferation requirements, creating a situation where Saudi Arabia appears unlikely to settle for a US deterrent alone. The kingdom has been pursuing a nuclear program for years and is well on its way to bringing a reactor online. It has stockpiled nuclear ore for many years; according to The Guardian, Saudi Arabia in 2020 already had enough uranium ore to produce some ninety thousand tons of purified uranium. In 2023, the nation's Energy Minister revealed plans to develop a full nuclear cycle — producing yellowcake uranium, enriching it, and producing nuclear fuel that Saudi Arabia eventually plans to export.

Critically, Saudi Arabia already possesses intercontinental ballistic missiles capable of mounting warheads, courtesy of China but reportedly with the sign-off of the American CIA. Under a Trump administration, it is not terribly likely that Saudi Arabia would face sanctions for pursuing the bomb in a world where Iran's nuclear program had gone operational. The kingdom would probably need international support to quickly develop elements of a weapons program it currently lacks, but it could solicit that support from either a friendly United States or a friendly China — and given the competitive dynamic between those two nations, both potential backers might be eager to agree. In a worst-case scenario, Saudi Arabia may need five years to get nuclear weapons operational, and possibly less.

<!-- aeo:section end="saudi-arabia-the-petrostate-shuffle-begins" -->
<!-- aeo:section start="the-cascade-effect-why-one-leads-to-many" -->
## The Cascade Effect: Why One Leads to Many

The central danger illuminated by this analysis is not any single nation's nuclear ambitions in isolation — it is the cascade effect. Each new nuclear-armed state fundamentally alters the security calculus of its neighbors and rivals, creating pressure for additional proliferation that existing treaties and diplomatic frameworks may be unable to contain.

Consider the chain: Iran's breakout capability pressures Saudi Arabia and Turkey. Poland's pursuit of a deterrent gives Turkey justification within NATO and signals to the broader alliance that proliferation norms are weakening. South Korea's program validates the logic of independent deterrents for nations that feel abandoned by the United States, potentially influencing Japan and others in the Indo-Pacific. France expands its arsenal under pressure to compensate for a diminished American umbrella. Each link in the chain makes the next link more likely.

The treaties designed to prevent this — the Nuclear Nonproliferation Treaty, the Comprehensive Nuclear-Test-Ban Treaty, and various bilateral agreements — depend on a combination of great-power enforcement, security guarantees, and shared norms. When the guarantees become unreliable, the enforcement becomes selective, and the norms begin to erode, the entire architecture is at risk. Arms-control experts have long warned that the system is only as strong as its weakest link, and in early 2025, multiple links appear to be straining simultaneously.

<!-- aeo:section end="the-cascade-effect-why-one-leads-to-many" -->
<!-- aeo:section start="timelines-and-the-path-to-twenty-nuclear-powers" -->
## Timelines and the Path to Twenty Nuclear Powers

If Poland, South Korea, and Iran all began confirmed efforts to build nuclear weapons — not necessarily producing finished products, but visibly traveling down that path — the resulting cascade could plausibly bring the world to twenty or more nuclear-armed states by 2040. The timelines vary considerably by nation: Iran could achieve breakout within months, South Korea within two to three years, Poland within five years at minimum, Turkey within three to ten years, and Saudi Arabia within roughly five years.

These timelines are not fixed; they depend on the level of international support or opposition each nation encounters, the degree to which existing alliances hold or fracture, and the willingness of established nuclear powers to either assist or obstruct new entrants. What makes the current moment uniquely dangerous is that many of the factors that historically restrained proliferation — reliable American security guarantees, strong nonproliferation norms, and great-power consensus against new nuclear states — are all weakening at the same time.

The world has lived with nine nuclear powers for years, and the balance, while precarious, has held. The prospect of twelve, fifteen, or twenty nuclear-armed states represents a fundamentally different kind of risk — not merely more of the same danger, but a qualitative transformation of the global security environment in which the probability of miscalculation, accident, or deliberate use rises with every new entrant to the nuclear club.

<!-- aeo:section end="timelines-and-the-path-to-twenty-nuclear-powers" -->
<!-- aeo:section start="the-united-arab-emirates-a-gold-standard-agreement-under-strain" -->
## The United Arab Emirates: A Gold-Standard Agreement Under Strain

From Saudi Arabia, the proliferation lens naturally shifts to its next-door neighbor, the United Arab Emirates. The UAE is generally considered one of the nations most resistant to its nuclear urges, owing in large part to a collaborative agreement with the United States that is widely regarded as the global gold standard for getting nations with civil nuclear programs to commit to avoiding weapons proliferation. But the UAE is already considerably more advanced on nuclear power than either Turkey or Saudi Arabia. As of 2024, the Emirates is operating all four reactors at its first nuclear power plant, with plans to build more.

The considerations here are fundamentally geopolitical. The UAE shares a growing rivalry with Saudi Arabia, with the two nations competing on an ever-larger scale each year. When it comes to international prestige and strategic leverage, there is no greater triumph than procuring a nuclear weapon. For the UAE to sit quietly by while Saudi Arabia, Turkey, and Iran all acquire nuclear weapons is not a likely scenario. While the nation's gold-standard agreement with the United States would almost certainly preclude an Emirati bomb in today's world, the hypothetical under discussion is not today's world — it is a world where the international nuclear order is already breaking down rapidly, and where today's approach to arms control has been turned on its head.

The UAE is one of those nations with a nuclear program currently understood to be proliferation-proof. But if the Emirates were to start down the path to a bomb, the timeline would likely resemble Turkey's: perhaps as few as three years, perhaps as many as ten — but with the potential added benefit of assistance from nations looking to spite the Saudis on their own doorstep. Other petrostates worthy of consideration include Qatar and Azerbaijan, although neither nation appears to be in a position to start a nuclear weapons program anytime soon.

<!-- aeo:section end="the-united-arab-emirates-a-gold-standard-agreement-under-strain" -->
<!-- aeo:section start="egypt-a-rising-power-with-a-nuclear-past" -->
## Egypt: A Rising Power With a Nuclear Past

Moving to North Africa, Egypt — itself a neighbor to Saudi Arabia in all but the most pedantic technicalities — is another rising power that deserves serious consideration. After years on ice, Egypt restarted its nuclear power program in 2013, and that program is now well underway as the nation builds the El-Dabaa Nuclear Power Plant on the Mediterranean coast. The Russian-backed initiative should yield a functioning reactor within the next decade, and Israel has expressed interest in a second reactor as well.

Egypt is another nation with nuclear weapons in its past, and it has conducted experimentation into other weapons of mass destruction, working toward offensive biological weapons and deploying chemical weapons in the 1960s. The nation possesses ample delivery mechanisms for a nuclear weapon, and prominent ex-military officials have suggested that in a world where Iran obtains nuclear weapons — and especially if Turkey and Saudi Arabia follow — Egypt would be forced to procure weapons of its own.

But even if the threat of a nuclear Middle East were not enough to prompt an Egyptian bomb, a nuclear Ethiopia almost certainly would be. Egypt and Ethiopia are cultivating an emerging and bitter rivalry in northern Africa, at a time when Ethiopia under its autocrat Abiy Ahmed is working hard to become a regional power somewhere between Erdogan and Kim Jong-un on the unpredictability spectrum. Ethiopia has considerable leverage over Egypt by way of its ability to control the flow of the Nile River, while Egypt is rapidly aligning itself with other nations concerned about Ethiopia's disruptive potential. Both Egypt and Ethiopia could potentially develop nuclear weapons within a decade if they secured the right international support — or perhaps within fifteen years under more conservative estimates.

<!-- aeo:section end="egypt-a-rising-power-with-a-nuclear-past" -->
<!-- aeo:section start="ethiopia-and-eritrea-africa-s-unlikely-nuclear-contenders" -->
## Ethiopia and Eritrea: Africa's Unlikely Nuclear Contenders

Ethiopia's inclusion on any list of potential nuclear proliferators may seem surprising, but the nation's trajectory under Abiy Ahmed makes it a genuine consideration in a cascading scenario. Ahmed asked France to station nuclear missiles on Ethiopian territory as far back as 2019, and the nation is working on a civilian nuclear power program via cooperation with Russia. Ethiopia, along with most of Africa, has long advocated the preservation of the continent as a nuclear-weapons-free zone, but if there is any leader likely to abandon those pledges at a time when nuclear proliferation is ongoing, it is Abiy Ahmed.

Ethiopia would probably take quite a while to develop nuclear weapons on its own, if it could ever get there at all. However, in a world where the Middle East is already going nuclear and the old order of nonproliferation is breaking down fast, Ahmed's broader desire to turn Ethiopia into a regional power — combined with his proven tendency to disregard international rules and norms — could make a push to develop a nuclear warhead a realistic possibility. Support from any number of actors, from the UAE to Russia, might be forthcoming as well.

Perhaps most unexpectedly, if Ethiopia were to go nuclear, one other nation would start to look at the bomb: Eritrea. Outwardly, a state in such obvious internal shambles as Eritrea would not be a likely candidate to build a nuclear weapon or even come close. The trouble, however, is the closeness between a nation often referred to as 'the North Korea of Africa' and the actual nation of North Korea. Eritrea shares ties with North Korea, and the two nations have even engaged in under-the-table military collaboration. In a world where even Ethiopia is looking at acquiring warheads, Eritrea would be under real pressure to at least try asking North Korea for support — either to station North Korean warheads as a deterrent or to help Eritrea develop its own program, similar to the circumstances under which North Korea accelerated its own program in the early 2000s. Given the chance for North Korea to both profit from selling nuclear secrets and to start building a sphere of influence a whole continent away, it is not necessarily assured that Pyongyang would refuse.

<!-- aeo:section end="ethiopia-and-eritrea-africa-s-unlikely-nuclear-contenders" -->
<!-- aeo:section start="japan-the-world-s-most-nuclear-ready-non-nuclear-state" -->
## Japan: The World's Most Nuclear-Ready Non-Nuclear State

If South Korea were to begin a nuclear weapons program, it is all but assured that North Korea would step up its own efforts to the extent it is able. But it is the threat of a potentially more aggressive, more belligerent North Korea that draws in the nation of Japan.

It should be no surprise that Japan, as the only nation ever to have nuclear weapons used against it, is not particularly friendly to the idea of a nuclear program of its own. But at the same time, Japan is easily the world's nation with the most firmly established latent capability to produce nuclear weapons if it ever needed to. Japan abandoned its goal to phase out nuclear power after the 2011 Fukushima disaster and is now working to increase its reliance on civilian nuclear energy, with the intent of supplying a fifth of the nation's electricity that way by 2030. As a result of its long-running nuclear power program, Japan is in possession of a substantial quantity of weapons-grade plutonium — enough to create well over five thousand nuclear bombs through that method alone, without even accounting for the enriched uranium in Japan's possession.

Japan has become the only nation in the world that possesses a full nuclear fuel cycle without nuclear weapons, and it has robust delivery mechanisms for a warhead if it ever decided to make one. The nation has innumerable nuclear scientists of its own, plus an exceptionally close relationship with the United States, to the point that a Japanese effort to build a warhead might even enjoy direct American support under the right circumstances.

The nation's current prime minister has called for Japan to consider sharing US nuclear weapons on its soil, and former Prime Minister Shinzo Abe brought nuclear weapons back into the national discourse after decades of treating them as taboo following Hiroshima and Nagasaki. While the Japanese public is not currently in favor of acquiring a nuclear bomb, it may face a situation similar to South Korea's, where changing international circumstances drive the public to change their minds. If South Korea believes it must develop a bomb — probably because of signs of waning US support that Japan would observe too — then the likely outcomes, from North Korean aggression to broader regional destabilization and a potential invasion of Taiwan, would push Japan to act quickly. Although there is no concrete timeline for Japan to produce a warhead if it began work today, a conservative estimate places the latency period at just six months — and under the right circumstances, it could accomplish the task in a mere fraction of that time.

<!-- aeo:section end="japan-the-world-s-most-nuclear-ready-non-nuclear-state" -->
<!-- aeo:section start="australia-a-shifting-nuclear-calculus-in-the-pacific" -->
## Australia: A Shifting Nuclear Calculus in the Pacific

Less likely to take the plunge but not entirely unlikely is Australia, where public opinion on nuclear matters has shifted rapidly in recent years. From a nation long hesitant to engage with anything even remotely nuclear-shaped, Australia now appears as if it may construct reactors at no fewer than seven sites nationwide, should the leader of Australia's opposition, Peter Dutton, be elected to office. The nation is also developing nuclear-powered submarines with American and British support, and it hosts a full one-third of the world's uranium deposits.

Australia previously formed a plan to develop plutonium for nuclear weapons production during the Cold War. Today, almost two-thirds of Australians support both the adoption of nuclear power and the adoption of nuclear submarines — both figures vastly increased from prior decades. Perhaps most tellingly, thirty-six percent of Australians supported acquiring nuclear weapons in 2022, as opposed to just twenty percent in 2010. Developments abroad may well prompt the Australian public to shift its position further.

In a world where the United States may begin to pull back from its international partnerships, it is Australia alongside Japan and South Korea that would form a bulwark against Chinese ambitions in the Pacific. While Australia would not be likely to pursue nuclear weapons tomorrow, in a nuclear cascade scenario — particularly one in which Australia would risk being left behind as its regional partners arm themselves — the calculus could change dramatically.

<!-- aeo:section end="australia-a-shifting-nuclear-calculus-in-the-pacific" -->
<!-- aeo:section start="germany-europe-s-reluctant-last-domino" -->
## Germany: Europe's Reluctant Last Domino

If Japan were to utilize its breakout potential and produce a nuclear bomb, the ripple effects would extend all the way back to continental Europe, where Germany would emerge as one more contender. As previously noted, Germany is a nation where the United States currently stations warheads, but it has been deeply reticent to develop its own nuclear weapons program for a very long time. A large part of Germany's hesitance has actually come from following Japan's lead. As the two nations that led the losing coalition in the most devastating war in human history, Japan and Germany have made it a point to avoid seeking out weapons of mass destruction. Germany even swore off its civil nuclear program after the Fukushima disaster of 2011 — even after Japan reversed course on its own deactivation initiative.

Yet as in so many other nations, the German public is slowly reversing course on nuclear weapons. A 2022 poll found for the first time in decades that a majority of the public approved of the presence of US nuclear weapons in Germany. The country's former leader, Olaf Scholz, spent a fair portion of his time pushing against nuclearization talk in Germany, but Scholz has been voted out, and his successor, Friedrich Merz, is pushing for weapons-sharing agreements with Britain and France.

Germany has the technical capabilities to invest in a nuclear program if it wished to. Although the nation still does not seem inclined to build those weapons today, the combination of a new nuclear neighbor in Poland, plus a tacit or even explicit expression of support from a nuclearizing Japan, could be enough to push Germany over the edge. If the nation were to reverse course — unlikely as that may be — it may not take very long to go operational, given its technical knowledge, military assets, and likely support from several allied nations.

<!-- aeo:section end="germany-europe-s-reluctant-last-domino" -->
<!-- aeo:section start="the-speed-of-collapse-why-the-cascade-could-unfold-faster-than-e" -->
## The Speed of Collapse: Why the Cascade Could Unfold Faster Than Expected

One of the most critical and underappreciated dimensions of a nuclear cascade is how fast it could unfold. The timelines discussed throughout this analysis — months for Iran, two to three years for South Korea, five years for Poland, and so on — assume that each nation begins its program in sequence, responding only after a predecessor has completed its first warhead. In reality, nations that know or even suspect that their adversaries are building a bomb have no incentive to wait until there is proof of detonation before responding.

Nations might try to delay because of the fear of repercussions from the international order, but that is precisely the order that is falling apart. If nations feel at liberty to start their own nuclear programs as soon as their adversaries do the same, then a cascade would not necessarily take years to play out. A particularly catastrophic six-week stretch of diplomatic breakdown could be enough to set the entire chain in motion — and the world has experienced several such stretches in recent memory.

This acceleration dynamic means that the window for intervention is far narrower than it might appear. By the time the international community recognizes that a cascade is underway, multiple nations may already be well down the path to weaponization, making diplomatic reversal exponentially more difficult with each passing week.

<!-- aeo:section end="the-speed-of-collapse-why-the-cascade-could-unfold-faster-than-e" -->
<!-- aeo:section start="deterrents-against-the-cascade-what-could-still-prevent-it" -->
## Deterrents Against the Cascade: What Could Still Prevent It

For all the alarm warranted by the current trajectory, there are significant protections that may prevent even the start of this cascade from coming to pass. Iran is under severe international pressure, including the threat of a US bombing campaign, and hardliners in Washington have indicated that, at least on paper, they are willing to deliver considerable force to prevent Iran from acquiring the bomb. South Korea and Poland, if they chose to pursue nuclear programs, could each face intense backlash from their allies — Poland potentially ostracized from NATO and sanctioned heavily by the European Union, South Korea stranded on its own against North Korea and China on its doorstep.

Adversaries, too, serve as deterrents. China or Russia would be just as likely to attempt pre-emptive action against South Korea and Poland, respectively, as the United States would be against Iran. All those deterrents, stacked on top of one another, could be enough to stop each nation from taking the leap — and the same is true for every other potential proliferator discussed in this analysis.

Yet the broader geopolitical environment complicates even these protections. Long regarded as the guarantor of global security, the so-called 'rules-based international order' risks becoming a thing of the past, as superpowers, regional powers, minor powers, and tiny nations alike push ever harder against boundaries that international norms were supposed to enforce. From Russia's incursion into Ukraine, to China's potential invasion of Taiwan, to America's potential abandonment of its allies abroad, those constraints are growing weaker by the day. The expectation that countries do not pursue nuclear weapons has been rock-solid for decades — but not anymore. And if that global rule is up for debate, then confidence in the rule above the rule — the global standard that calls for nations to stand together in opposition when a country goes rogue and pursues the bomb — becomes equally uncertain. If that falls apart, then it takes only one nuclear-armed nation supporting allies in their nuclear ambitions for the world to descend into a proliferation race.

<!-- aeo:section end="deterrents-against-the-cascade-what-could-still-prevent-it" -->
<!-- aeo:section start="rational-actors-irrational-outcomes-the-paradox-at-the-heart-of-" -->
## Rational Actors, Irrational Outcomes: The Paradox at the Heart of Proliferation

Perhaps the most unsettling dimension of the nuclear cascade scenario is that it does not require a single irrational actor to unfold. Every nation discussed in this analysis — from Poland to South Korea to Iran to Saudi Arabia to Japan to Germany — has its own clear set of incentives to take the leap. Nowhere in the chain does there have to be an absolutely mad dictator determined to follow a ludicrous path to its worst conclusion. Instead, the cascade consists of rational nations forming rational responses to other rational nations, all of whom can thoroughly justify the part they individually play in a chain reaction that is bigger than any of them.

If an era of sudden nuclear proliferation is going to come from anything, it will come from this: a moment in history when several nations, perhaps even a dozen or more, each pivot to address new challenges from the world around them. Each nation takes a series of steps that it believes will protect its interests, its sovereignty, and its place on the world stage, as any nation would. Then, at the logical conclusion of each of those series of steps, those nations find a nuclear warhead.

In Poland, in South Korea, and to an extent even in Iran, that is precisely what is happening now. Donald Tusk, Han Duck-soo and his likely successor Lee Jae-myung, even the Ayatollah Ali Khamenei — they are not stupid, and they are not insane. They are marching down the path to a nuclear bomb because that is what they believe would make sense. And it is in a world where nuclear proliferation makes sense that the entire world needs to prepare for what comes next.

<!-- aeo:section end="rational-actors-irrational-outcomes-the-paradox-at-the-heart-of-" -->
<!-- aeo:section start="a-more-likely-outcome-not-twenty-but-how-many" -->
## A More Likely Outcome: Not Twenty, But How Many?

The worst-case scenario outlined in this analysis — a world with twenty or more nuclear-armed states by 2040 — represents a full breakdown of the post-World War II nuclear order, a complete abandonment of the modern rules of nonproliferation that govern today's world. In such a world, perhaps not all the nations discussed would ultimately take the leap — but perhaps others would, like Brazil, Canada, Italy, or others not yet on anyone's radar.

The odds of the full worst-case scenario remain slim. But the purpose of tracing the cascade to its logical extreme is not to predict the future with certainty — it is to illustrate the grave importance of the nuclear conversations happening today. From Poland to South Korea to Iran, there are real and ongoing discussions about whether to develop an operational nuclear capability. Even if the outcome is not the full worst-case scenario, it could very well be a sequence of repercussions in which significant parts of this cascade do play out. There are a great many outcomes less catastrophic than twenty nuclear powers that still manage to be very bad in their own right.

The world has nine nuclear nations today, and it may not have twenty by 2040. But how certain can anyone be that the world will not have twelve? How certain can anyone be that it will not have fifteen? By examining the full scope of the cascade — from the first domino to the last — policymakers and publics alike can better understand the risk of even a partial proliferation spiral, and the urgency of acting before the chain reaction begins.

<!-- aeo:section end="a-more-likely-outcome-not-twenty-but-how-many" -->
<!-- aeo:section start="related-coverage" -->
## Related Coverage
- [The UAE is Destabilizing the Entire Middle East](https://warfronts.pub/conflicts/the-uae-is-destabilizing-the-entire-middle-east)
- [The UAE's Regional Ambitions Collapse as Middle East Powers Push Back](https://warfronts.pub/geopolitics/uae-regional-ambitions-collapse-middle-east-pushback)
- [How the UAE's Regional Meddling Triggered a Historic Realignment Across the Middle East](https://warfronts.pub/geopolitics/uae-destabilizing-middle-east-regional-realignment-2026)

<!-- aeo:section end="related-coverage" -->
<!-- aeo:section start="faq" -->
## FAQ

### How soon could Poland realistically acquire nuclear weapons?

Poland faces significant hurdles and would need at least five years to develop nuclear weapons, with 2030 representing the absolute floor for a realistic Polish nuclear capability. The nation currently has no civilian nuclear power installations, with its first reactors not expected until after 2030, and lacks the institutional knowledge from running a prior nuclear weapons program. There is a possibility that France, the United States, South Korea, or another ally could offer support through a joint program or framework of mutual assistance.

### What is a nuclear cascade and why is it so dangerous?

A nuclear cascade is a chain reaction of proliferation in which one nation's decision to acquire nuclear weapons triggers others to do the same, creating a self-reinforcing spiral. Each new nuclear-armed state fundamentally alters the security calculus of its neighbors and rivals, creating pressure for additional proliferation. The danger is that this represents a qualitative transformation of the global security environment, where the probability of miscalculation, accident, or deliberate use rises with every new entrant to the nuclear club.

### Which countries would most likely follow if Poland, South Korea, and Iran go nuclear?

Turkey would be a prime candidate within NATO if Poland pursues nuclear weapons, having hinted at developing the bomb since 2019. Saudi Arabia has openly stated it will build a nuclear arsenal if Iran develops one. Japan, with its massive plutonium stockpile, could respond to a South Korean program within six months. Other potential proliferators include the UAE, Egypt, Ethiopia, Australia, and potentially Germany if Japan were to go nuclear.

### How quickly could Japan develop a nuclear weapon if it decided to?

Japan exists in a state of extremely high nuclear latency and could produce a functional warhead within six months under conservative estimates, and potentially in a fraction of that time under the right circumstances. Japan possesses enough weapons-grade plutonium to create well over five thousand nuclear bombs, has a full nuclear fuel cycle, robust delivery mechanisms, innumerable nuclear scientists, and an exceptionally close relationship with the United States that might even provide direct support.

### What role does uncertainty about US security commitments play in nuclear proliferation?

Erosion of confidence in the American nuclear umbrella is a structural driver of proliferation. Donald Trump's second term has generated widespread concern among US allies about whether Washington will honor its commitments to defend other nations in times of war. This ambiguity pushes nations to consider managing their own defense independently. When allied nations can no longer trust that the world's largest nuclear power will come to their defense, the incentive to develop independent deterrents becomes overwhelming.

<!-- aeo:section end="faq" -->
<!-- aeo:section start="sources" -->
## Sources
- <https://www.politico.eu/article/donald-tusk-plan-train-poland-men-military-service-russia/>
- <https://www.nytimes.com/2025/03/07/world/europe/poland-nuclear-trump-tusk.html>
- <https://www.cbsnews.com/news/poland-president-duda-us-nuclear-weapons-deploy/>
- <https://www.iiss.org/publications/strategic-comments/2023/polands-bid-to-participate-in-nato-nuclear-sharing/>
- <https://www.atlanticcouncil.org/blogs/new-atlanticist/why-polands-president-wants-us-nuclear-weapons/>
- <https://breakingdefense.com/2025/03/a-nuclear-poland-logistics-political-challenges-ahead-of-potential-warsaw-deal/>
- <https://www.euronews.com/2025/03/21/could-another-european-country-develop-its-own-nuclear-weapons>
- <https://ip-quarterly.com/en/future-zeitenwende-scenario-5-poland-becomes-nuclear-power>
- <https://world-nuclear.org/information-library/country-profiles/countries-o-s/poland>
- <https://foreignpolicy.com/2024/09/22/south-korea-nuclear-weapons-proliferation-deterrence-strategy/>
- <https://www.nytimes.com/2024/08/17/world/asia/south-korea-nuclear-arsenal.html>
- <https://www.cato.org/commentary/why-south-korea-wants-nuclear-weapons-now-more-ever>
- <https://www.foreignaffairs.com/north-korea/why-south-korea-should-go-nuclear-kelly-kim>
- <https://theconversation.com/nuclear-war-threat-why-africas-pushing-for-a-complete-ban-253171>
- <https://warontherocks.com/2024/09/south-koreas-nuclear-latency-dilemma/>
- <https://carnegieendowment.org/research/2024/03/playing-with-proliferation-how-south-korea-and-saudi-arabia-leverage-the-prospect-of-going-nuclear?lang=en>
- <https://www.orfonline.org/expert-speak/south-korea-s-quest-for-nuclear-weapons>
- <https://www.reuters.com/world/trump-says-there-will-be-bombing-if-iran-does-not-make-nuclear-deal-2025-03-30/>
- <https://www.cfr.org/article/what-are-irans-nuclear-and-missile-capabilities>
- <https://apnews.com/article/iran-nuclear-iaea-weapons-grade-uranium-trump-0b11a99a7364f9a43e1c83b220114d45>
- <https://thebulletin.org/2025/01/how-quickly-could-iran-build-its-first-nuclear-weapon-look-at-china/#:~:text=Some%20nuclear%20experts%20argue%20it,as%20three%20to%20five%20weeks>
- <https://isis-online.org/isis-reports/detail/how-quickly-could-iran-make-nuclear-weapons-today/8>
- <https://foreignpolicy.com/2024/10/10/iran-nuclear-weapon-warhead-missile-how-soon/>
- <https://nordicmonitor.com/2024/09/turkey-needs-to-acquire-nuclear-arms-to-stop-israel-urges-erdogans-chief-fatwa-giver/>
- <https://www.iar-gwu.org/blog/erdogans-nuclear-itchstrong-strongwhy-turkeys-nuclear-program-is-a-threat-to-regional-stability-and-the-international-nonproliferation-regime>
- <https://www.brookings.edu/articles/its-time-to-get-us-nukes-out-of-turkey/>
- <https://www.fdd.org/in_the_news/2025/02/05/faq-is-turkey-the-next-nuclear-proliferant-state/>
- <https://www.armscontrol.org/act/2019-10/news/turkey-shows-nuclear-weapons-interest>
- <https://www.reuters.com/article/world/erdogan-says-its-unacceptable-that-turkey-cant-have-nuclear-weapons-idUSKCN1VP2Q8/>
- <https://thebulletin.org/2024/12/the-rise-and-fall-of-swedens-nuclear-disarmament-advocacy/>
- <https://www.icanw.org/sweden_nato_and_the_irresponsible_calls_for_more_nuclear_sharing_in_europe>
- <https://www.bbc.com/future/article/20240412-the-secret-scandinavian-a-bomb-project>
- <https://www.politico.com/news/magazine/2024/07/04/europe-us-nuclear-weapons-00166070>
- <https://www.reuters.com/world/europe/how-realistic-is-frances-offer-extend-its-nuclear-umbrella-2025-03-06/>
- <https://warontherocks.com/2025/03/eurodeterrent-a-vision-for-an-anglo-french-nuclear-force/>
- <https://www.aftenposten.no/meninger/debatt/i/pPEOxj/norden-har-teknologien-og-pengene-til-aa-skaffe-seg-atomvaapen>
- <https://www.icanw.org/saudi_arabia>
- <https://www.nti.org/countries/saudi-arabia/>
- <https://georgetownsecuritystudiesreview.org/2024/12/18/the-nuclear-kingdom-accessing-saudi-arabias-nuclear-behavior/>
- <https://www.unav.edu/web/global-affairs/in-pursuit-of-the-bomb-is-saudi-arabia-playing-the-nuclear-game->
- <https://www.armscontrol.org/act/2023-11/news/saudi-push-enrichment-raises-concerns>
- <https://www.theguardian.com/world/2023/sep/21/crown-prince-confirms-saudi-arabia-seek-nuclear-arsenal-iran-develops-one>
- <https://foreignpolicy.com/2024/01/25/the-hidden-rivalry-of-saudi-arabia-and-the-uae/>
- <https://arabcenterdc.org/resource/the-uae-saudi-arabia-rivalry-becomes-a-rift/>
- <https://epicenter.wcfia.harvard.edu/blog/allies-odds-tracking-rivalry-between-saudi-arabia-and-united-arab-emirates>
- <https://world-nuclear.org/information-library/country-profiles/countries-a-f/egypt>
- <https://www.memri.org/tv/egypt-military-analyst-gen-samir-farag-if-iran-gets-nukes-we-want-them-too>
- <https://www.nti.org/countries/egypt/>
- <https://nucleus.iaea.org/sites/INPRO/df22/Day%203/3.2.Ethiopia.pdf>
- <https://www.thereporterethiopia.com/37427/>

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