Iran Wants to Go Nuclear: Which Other States Might Get the Bomb?

It was October 9th, 2006, when North Korea detonated a primitive nuclear device in its hinterland, becoming the newest member of the nuclear-armed club. In the nearly twenty years since, no other nation on Earth has crossed the nuclear threshold, leaving the group of nuclear-armed states steady at nine: the United States, Russia, the United Kingdom, France, China, India, Israel, Pakistan, and North Korea. Yet that remarkable stability may not last.

A small but growing number of countries are now openly discussing the possibility of going nuclear, and several possess both the technological capacity and the political conditions to do so. From sworn enemies of the West to putative allies, the stated desire to acquire nuclear weapons — and the ability to follow through — is spreading in ways that demand serious attention.

The Two Categories of Nuclear Aspirants

When assessing which nations could go nuclear, it is important to distinguish between countries where the conditions are right and those where they are spectacularly wrong. Most of the world’s nations fall into the latter category. In many cases, the barrier is purely technological — Libya under Gaddafi famously tried and failed to build a working bomb.

In other cases, a country may possess the technical knowhow but lack the political will. Japan, for example, has all the expertise needed to construct a working nuclear weapon in a short time, but its population overwhelmingly supports non-proliferation — over seventy percent in most surveys. As the Stimson Center wrote earlier this year, ‘Japanese public opinion toward nuclear disarmament remains strong, even as the strategic environment deteriorates with increasing nuclear risks.’

Even when conditions appear favorable, success is not guaranteed. Iraq nearly acquired the bomb in the early 1990s, only for American bombardments during the Gulf War to accidentally halt the program. Countries as diverse as Taiwan and South Africa have pursued nuclear weapons over the years, with South Africa even managing to clandestinely build a small number of devices it later dismantled.

What is unusual about the current moment is the sheer number of states openly talking about nuclear acquisition — and the fact that a small but growing number possess both the technology and the wider conditions to act, with little that outside actors could do to stop them.

Iranian Dreams: The Country Most Likely to Get the Bomb

That Tehran might want the bomb is unlikely to be news to anyone paying attention. As far back as the reign of the Shah, Iran carried out research into nuclear weapons. In the aftermath of the Iran-Iraq War, Tehran invested heavily in a nuclear program out of fear that Iraq would get there first.

Although this program was suspended in 2003, the technology was already highly advanced. Since then, there have been constant suspicions that the regime is ensuring it stands on the nuclear threshold — never quite crossing, but close enough that it could do so at short notice. As the Atlantic explains, ‘The trouble is that civil nuclear efforts can be “double purposed” — meaning that even without any specific work on weaponization, Iran’s nuclear advances have brought it dangerously close to producing a bomb.’

The Obama-era Joint Comprehensive Plan of Action (JCPOA), unveiled in 2015, was designed to address these fears. The deal lifted sanctions in exchange for Tehran heavily cutting back its stockpile of enriched uranium. According to Reuters, the agreement ‘slashed Iran’s stock of enriched uranium, leaving it only with a small amount enriched to up to 3.67% purity, far from the roughly 90% purity that is weapons grade.

The United States said at the time that a main aim was to increase the time Iran would need to produce enough fissile material for a nuclear bomb to at least a year.’ However, when President Trump walked away from the deal in 2018, Tehran was back on the path toward the bomb within a year. By spring of 2024, the UN reported that Iran’s stockpile of enriched uranium had risen from the 202.8 kg enshrined in the JCPOA to 5.5 tonnes, with enrichment levels reaching 60 percent purity — only a little below weapons grade.

As the Atlantic noted, ‘Iran is the only nonnuclear weapons state in the world to have enriched uranium to such levels.’ While Iran’s people elected Masoud Pezeshkian, who campaigned as a moderate on the nuclear issue, the reality of the Iranian system means the decision to go nuclear will not rest with him. The Council on Foreign Relations has observed that ‘the position of the Iranian regime has been that, because the United States left the agreement and imposed sanctions on Iran, Washington has to come back in compliance before talks resume.

This was the position of the Hassan Rouhani and Raisi governments. It could well end up being the position of the Pezeshkian government.’ In practical terms, little may have changed since May 9th, when former foreign minister Kamal Kharazi threatened that Iran would go nuclear if Israel ever threatened its interests.

Crossing the Threshold: Iran’s Breakout Time

When experts discuss how long it would take a country to acquire nuclear weapons, they typically refer to ‘breakout time’ — the length of time needed to produce sufficient weapons-grade uranium for a bomb. In Iran’s case, that breakout time is alarmingly short. Physicist and weapons expert David Albright has written that ‘Today, Iran would need only about a week to produce enough for its first nuclear weapon.’

In the same paper, published earlier this year, Albright estimates that Tehran could have enough weapons-grade uranium for six nuclear weapons within a month, and enough for twelve within five months. He also notes that Iran has delivery systems ready to go, including nuclear-capable missiles. However, breakout time only refers to uranium enrichment.

Building a working bomb requires the far more complex process of weaponization, which includes, as Albright describes, ‘the mastery of the high explosive triggering system, the molding and machining of high explosives, and the building of a neutron initiator that starts the chain reaction at just the right moment to create a nuclear explosion.’ This is where Iran would face its main hurdle. Before his retirement, Chairman of the Joint Chiefs of Staff General Mark Milley estimated that the weaponization process would take ‘several months,’ while other expert assessments have estimated as long as a year.

Albright further notes that Iran getting into a position where it can ‘serially produce annually many warheads suitable for delivery by ballistic missiles’ could take ‘a few years’ and almost certainly could not be done in secrecy. If Iran were to try and become a serious nuclear player, the international community would know about it long in advance. The bad news is that Iran does not necessarily need multiple missile-deliverable warheads to achieve its goals.

Simply assembling a handful of crude nuclear devices and detonating one at a test site might be enough to demonstrate that Tehran is serious. The assembly time for a crude device is far shorter — in the region of six months. Given that Iran could hold off enriching its uranium to suitable levels until the process is far along, Albright reckons the international community might get as little as two months’ notice that Tehran had decided to go nuclear.

That is not long to act, but it is not nothing. Were the alert to go out across intelligence agencies, the United States would be expected to react harshly, and Israel could go even further — perhaps unleashing a kinetic response against Iran’s nuclear facilities. But with Iranian nuclear production dispersed across multiple sites, it might take more than a few missile attacks to dislodge Tehran from its course.

The end result could still be Iran testing a crude device only a little later than originally planned.

Why Iran Hasn’t Gone Nuclear Yet

Given how close Iran is to the bomb, the question of why it has not yet taken the final step is a critical one. The most obvious answer is fear. As Foreign Policy has summed it up, ‘Tehran may be deterred by the threat of preventive war.’

But there are other reasons as well. Analyst Karim Sadjadpour has suggested Iran may be pursuing the ‘Japan option’ — getting to the point where it could make a bomb in next to no time, but refraining from doing so. In Iran’s case, this would keep the threat viable without inviting retaliation.

Others have pointed to Supreme Leader Ayatollah Ali Khamenei’s fatwa against the use of nuclear weapons, suggesting he may truly believe they are un-Islamic, however unlikely that may seem. It could also simply be that Tehran currently sees no need to go nuclear because it does not believe the United States or Israel pose an existential threat. Whatever the reason, something has so far stopped Iran from becoming the tenth member of the nuclear weapons club.

K-Bomb: South Korea’s Nuclear Calculations

On the face of it, South Korea would seem an unlikely contender to join the nuclear club. Despite having an aggressive, militaristic northern neighbor, it is protected by an alliance with the most powerful nation on Earth — an alliance that commits Washington to a kinetic response if South Korea is attacked. Tens of thousands of U.S. troops are stationed in the country, many right near the border with North Korea.

Were Pyongyang to attack, so many Americans would be killed that the United States would have no choice but to respond with force. Apart from a brief attempt in the 1970s, South Korea has never pursued nuclear weapons. Yet the last couple of years have seen significant shifts in Korean thinking about the bomb.

Polls now show that between seventy and eighty percent of South Koreans want their country to have nuclear weapons. In January 2023, President Yoon Suk Yeol even said that South Korea could ‘acquire our own nukes if the situation gets worse. It would not take long.’

Although he later walked back his comments, the fact that he made them at all shows how profoundly Seoul’s perspective is changing. This shift has been driven by developments in two specific nations: North Korea and the United States. Like many American allies, Seoul is more than a little worried about the potential return of Trump as president.

During his first term, President Trump not only questioned the need for joint military exercises between the U.S. and South Korea but also insisted Seoul pay billions of additional dollars to keep U.S. bases open on its soil. This transactional approach coincided with Pyongyang making a series of technological breakthroughs in developing missiles capable of delivering nuclear warheads to U.S. territory. Initially, possible targets were limited to places like Guam and Hawaii.

Today, however, the Hwasong-18 is thought capable of striking the U.S. mainland. For Seoul, this has been a strategic game changer. As AP News put it, ‘The fear is this: That a U.S. president would hesitate to use nuclear weapons to defend the South from a North Korean attack knowing that Pyongyang could kill millions of Americans with atomic retaliation.’

The Ukraine War has further exacerbated these worries. American allies in Asia have watched the conflict with growing concern, and one of the main takeaways in Seoul has been Western hesitancy to stand up to nuclear-armed Russia. If friendly nations are scared of a relatively rational autocrat like Putin using nuclear weapons, the thinking goes, how would they react to a genuine madman like Kim Jong-Un threatening to deploy them?

The Biden White House tried to calm these fears by signing a document on joint nuclear deterrence on July 11th, but if Trump returns, that document could be almost worthless. The former head of South Korea’s special forces captured the mood when he told the Financial Times earlier this year: ‘I have never doubted an American soldier. But I would be foolish to place my nation’s security in the hands of an American politician.‘

Limits and Likelihoods: Could South Korea Actually Build the Bomb?

Going nuclear is unlikely to be a decision South Korea would take lightly. Unlike North Korea or Iran, it is not a pariah state already cut off from most of the world economy, and the penalties for breaking the Non-Proliferation Treaty could be harsh. The Diplomat notes that sanctions could be slapped on Seoul by the UN as punishment, and the United States would also react harshly, perhaps depriving the Koreans of one of their key allies.

There would also be concerns about the reaction from Seoul’s neighbors. At the lower end of the scale, Japan might be convinced to also go nuclear were South Korea to detonate a device. At the higher end, Beijing might get involved.

As the Diplomat writes, ‘Seoul would also face China’s reaction to its nuclear development, further increasing the pressure on South Korean security.’ Given these possible downsides, Seoul would want to make sure that the security guarantees nuclear weapons would bring are worth the risk. In other words, it would have to seriously look like the Americans were losing interest in the region.

Since containing China’s rise is a bipartisan goal in Congress right now — and South Korea is a key part of that strategy — it is difficult to imagine such a scenario coming to pass, no matter how much Trump might grumble about the cost of maintaining U.S. bases on the peninsula. On a technical level, however, the answer to whether South Korea could build the bomb is a firm ‘yes.’ As the Carnegie Endowment for International Peace has written, South Korea ‘boasts one of the world’s most advanced civil nuclear energy enterprises, along with conventional strike and space launch capabilities that could be converted into nuclear delivery systems.

South Korea certainly has the technical capacity to build large enrichment or reprocessing facilities if it so desires.’ The critical caveat is in the phrase ‘if it so desires.’ Unlike Iran, South Korea does not have all the necessary infrastructure built and ready to go.

While Tehran might be capable of putting together a crude device and detonating it within six months, Seoul would have to wait longer. A 2018 report from the Pulitzer Center concluded that ‘it would take two to three years for South Korea to produce a nuclear bomb, including building some necessary infrastructure.’ Part of that time would be spent constructing a new reprocessing plant to make weapons-grade plutonium, and there might also be issues with having enough trained personnel to ‘build and run the back-end fuel cycle technologies required to produce the plutonium for a warhead.’

Once the plant was built, however, it would take just one year for Seoul to have enough fissile material for 20 warheads. The reason Seoul lags behind Tehran is at least partially due to the fact that, as the Carnegie Endowment notes, ‘restrictions in U.S.-Republic of Korea nuclear cooperation agreements have prevented Seoul from moving beyond small-scale enrichment and reprocessing experiments.’ Still, the nuclear option is clearly on the table for South Korea, even if overcoming the political fallout would be challenging.

Desert Bombs: Saudi Arabia’s Nuclear Rhetoric

Since at least 2018, Saudi Arabia has responded to hints that Iran might get the bomb with rhetoric suggesting that it, too, could seek to build a nuclear device. Most recently, this includes comments Crown Prince Mohammed bin Salman made to Fox News in September 2023, in which he made it clear that if Iran did build a nuclear weapon, ‘we will have to get one.’ To be fair, MBS went on to clarify that this was an extreme scenario and that he would prefer not to go nuclear.

Nonetheless, such threats have made some observers wonder if the Saudi kingdom might be a potential candidate for acquiring the bomb. This concern was recently turbocharged by talk of a potential nuclear deal between the Saudis and America. Driven by the Biden White House, the deal would see Riyadh agree to normalize ties with Israel in exchange for, among other things, the United States building a uranium enrichment facility on Saudi territory as part of a drive by the kingdom to switch its energy supplies to cleaner sources.

The trouble is that establishing such a plant could potentially give Riyadh access to nuclear technology that could be used to build a bomb. As Reuters summed it up, ‘Without rigorous safeguards built into an agreement, Saudi Arabia, which has uranium ore, could theoretically use an enrichment facility to produce highly enriched uranium, which, if purified enough, can yield fissile material for bombs.’ At the time of writing, the agreement has not yet gone ahead, and even if the White House seals the deal, it is not at all certain the enrichment facility will ever be built.

As the Carnegie Endowment points out, ‘a U.S. defense treaty requires ratification from two-thirds of the Senate.’ With a majority of senators from both parties skeptical about Riyadh’s nuclear hopes, it seems more likely than not that such a deal would be blocked in Congress.

Why Saudi Arabia’s Nuclear Ambitions Lack Credibility

Despite the rhetoric, the fundamental question remains: if the Saudis do not yet have an advanced civilian nuclear program, how would they ever build the bomb? According to the Carnegie Endowment for International Peace, the simple answer is that they are not in a position to do so. As the think tank writes, ‘Unlike South Korea, the country has no real nuclear latency to leverage.

It is still working to start a new research reactor while penning ambitious plans to import nuclear power plants and even enrich indigenous sources of uranium. The notion of the kingdom going nuclear is simply not credible.’ Beyond the technological gaps, there are significant political problems as well.

The Saudis attempting to build a nuclear device would cause a ferocious backlash from America and might also spark a war with Iran, which fears Saudi nuclear weapons almost as much as the Saudis fear Iranian ones. In short, while Saudi Arabia’s nuclear rhetoric serves as a useful signal of its strategic anxieties — particularly regarding Iran — the kingdom lacks the technological foundation, the nuclear latency, and the geopolitical room to maneuver that would be required to credibly pursue nuclear weapons in the foreseeable future.

A Shifting Nuclear Landscape

The current nuclear landscape is defined by a paradox: the club of nuclear-armed states has remained unchanged for nearly two decades, yet the conditions that sustained that stability are visibly eroding. Iran stands on the very edge of the nuclear threshold, with a breakout time measured in days and the potential to assemble a crude device within months. South Korea, a stalwart American ally, is openly debating nuclear acquisition as doubts grow about the reliability of U.S. security guarantees.

And Saudi Arabia, while far from possessing the technical capacity to build a bomb, is using nuclear rhetoric to signal its alarm over Iran’s advancing capabilities. What these three cases share is a common thread: the perception that the existing international order — built on alliances, treaties, and deterrence — may no longer be sufficient to guarantee national security. Whether any of these nations ultimately crosses the nuclear threshold will depend on a volatile mix of technological readiness, political will, alliance dynamics, and the actions of the current nuclear powers themselves.

The era of a stable nine-member nuclear club may be drawing to a close.

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Frequently Asked Questions

How close is Iran to building a nuclear weapon?

Iran could produce enough weapons-grade uranium for its first nuclear weapon in about a week, with enough material for six weapons within a month and twelve within five months. However, the weaponization process would take several months to a year. A crude nuclear device could potentially be assembled and detonated within roughly six months, giving the international community as little as two months’ notice.

Why hasn’t Iran already built nuclear weapons if it’s so close?

Several factors may be deterring Iran: fear of preventive war from the U.S. or Israel, the pursuit of the “Japan option” of maintaining capability without crossing the threshold to keep the threat viable without inviting retaliation, Supreme Leader Ayatollah Ali Khamenei’s fatwa against nuclear weapons, or the belief that the U.S. and Israel don’t currently pose an existential threat requiring nuclear deterrence.

Why is South Korea considering nuclear weapons despite being a U.S. ally?

South Korea’s shift is driven by two main concerns: North Korea’s development of missiles capable of striking the U.S. mainland, which raises fears that America might hesitate to defend South Korea if it means risking millions of American lives, and uncertainty about U.S. commitment following President Trump’s transactional approach to alliances during his first term. Between seventy and eighty percent of South Koreans now support acquiring nuclear weapons.

How long would it take South Korea to build a nuclear weapon, and is Saudi Arabia a credible contender?

It would take South Korea two to three years, including building a new reprocessing plant for weapons-grade plutonium. Saudi Arabia is far less credible: unlike South Korea, it has no real nuclear latency to leverage, is still working to start a basic research reactor, and the Carnegie Endowment for International Peace concludes that the notion of the kingdom going nuclear is simply not credible given its technological gaps.

What was the JCPOA and how did its collapse affect Iran’s nuclear program?

The Joint Comprehensive Plan of Action (JCPOA), unveiled in 2015, lifted sanctions on Iran in exchange for cutting its enriched uranium stockpile to 202.8 kg at up to 3.67% purity, aiming to keep Iran’s breakout time at least a year. When President Trump withdrew from the deal in 2018, Iran was back on the path toward the bomb within a year—by spring 2024 its stockpile had risen to 5.5 tonnes enriched to 60% purity, only slightly below weapons grade.

Sources

• https://isis-online.org/isis-reports/detail/how-quickly-could-iran-make-nuclear-weapons-today
• https://foreignpolicy.com/2024/05/14/iran-nuclear-weapon-strategy/
• https://foreignpolicy.com/2024/04/18/irans-nuclear-crisis-has-no-military-solution/
• https://www.reuters.com/world/middle-east/explainer-how-close-is-iran-having-nuclear-weapons-2024-04-18/
• https://www.theatlantic.com/international/archive/2024/05/iran-nuclear-program-threat/678514/
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• https://apnews.com/article/north-korea-south-korea-nuclear-arms-race-543e85e5e6832c50ba9dc26a91ef071b
• https://thediplomat.com/2024/05/the-great-debate-over-south-korea-developing-nuclear-weapons-is-back/
• https://carnegieendowment.org/research/2024/03/playing-with-proliferation-how-south-korea-and-saudi-arabia-leverage-the-prospect-of-going-nuclear
• https://carnegieendowment.org/posts/2024/06/saudi-us-deal-ratification-unlikely?lang=en
• https://www.reuters.com/world/how-might-us-saudi-civil-nuclear-deal-work-2024-05-18/
• https://pulitzercenter.org/stories/if-it-wanted-south-korea-could-build-its-own-bomb