Why Iran Now Wants the Bomb: Deterrence in the Shadow of the Mushroom Cloud

Deterrence. That is the word of the century in Iran, following what has been the nation’s most bruising conflict since the guns fell silent on the Iran-Iraq War. The last few weeks have seen the deaths of several of the country’s top officials, including former Supreme Leader Ali Khamenei. Losing key leadership figures is only part of the ledger.

The war has also exacted a heavy military cost on Tehran. According to Reuters, American intelligence believes Washington and Israel have destroyed about half of Iran’s drone and missile stockpiles, and that figure does not even count the missiles Iran expended in its own strikes against American and allied targets. Then there is the economic damage. Since the war began, the combined forces have systematically targeted Iran’s infrastructure and industries, inflicting losses worth tens of billions of dollars.

Analysts at Chatham House estimate the war will shrink Iran’s GDP by 10 percent.

Key Takeaways

Iran spent years pursuing a “threshold” strategy — staying just below weaponization while leaning on a regional proxy network — but the war proved that posture offered no protection at all.
The destruction of Hamas, the degradation of Hezbollah, and the fall of Bashar al-Assad’s regime in Syria collapsed the “axis of resistance” that underpinned Tehran’s layered deterrence.
Recent history — North Korea’s untouched arsenal, Russia’s nuclear-shielded invasion of Ukraine, and Ukraine’s surrender of inherited Soviet warheads — all point to the same conclusion: only nuclear powers reliably deter nuclear powers.
An Iranian bomb could trigger the largest proliferation cascade since the Cold War, with Saudi Arabia, Turkey, Egypt, and the UAE among the most likely followers — and second-order effects reaching South Korea, Japan, and Europe.
The bitter irony: the campaign launched to stop Iran from going nuclear may have made weaponization the most rational choice Tehran has left.

Given how much worse Tehran’s position is now compared to before the fighting, officials there must be asking a simple question: could this have been prevented? The uncomfortable answer is yes. There is one method that has worked extraordinarily well for fellow pariah state North Korea, and it is the same method that has defined the logic of great-power restraint for eighty years.

That method is nuclear weapons. The terrifying lesson of the 2020s so far is that they seem determined to prove the only true model of deterrence is one created in the shadow of the mushroom cloud.

Nuclear Dreams

“Iran’s nuclear ambitions” is a phrase we take for granted, because it is treated as a given that Iran wants the bomb. Yet there was a time when the highest levels of Iranian leadership said precisely the opposite. In an interview with a local Iranian outlet, former president Hassan Rouhani recounted Khamenei’s words directly: “No, we aren’t thinking about nuclear weapons. I have said many times that our nuclear weapon is this nation. Our nuclear weapons are these youths. We don’t want nuclear weapons.”

Rouhani added that he had told the foreign ministers of France, Germany, and the United Kingdom that this declaration by the Supreme Leader mattered more to Tehran than the Nuclear Non-Proliferation Treaty — the international agreement designed to prevent the spread of nuclear weapons and promote disarmament — or any other law meant to keep Iran from obtaining a bomb.

A natural reaction is skepticism: of course he would say that. No leader announces what is happening with the enriched uranium. Maybe it was all misdirection. But there are at least some reasons to believe Tehran was genuinely reluctant to take the final step toward assembling a working weapon.

The Fatwa and the Friction It Created

According to the Atlantic Council, Khamenei had previously called the use of nuclear arms haram — forbidden — a position that was popular with the Iranian people, with polls consistently showing opposition to developing nuclear weapons. This declaration became internationally recognized as a fatwa, which in Islam is a non-binding religious or legal opinion issued by a qualified scholar to clarify or resolve a question of Islamic law. A fatwa from the Supreme Leader, the country’s highest religious authority, should in theory represent a prohibition that shapes state policy.

In practice it created sharp friction between Khamenei and the IRGC. The Telegraph reported in 2025 that several senior Islamic Revolutionary Guard Corps commanders had been pressing Khamenei to rescind the fatwa in order to confront existential threats from the West. One official told the paper that, in the wake of Donald Trump’s reelection, Iran had never been more vulnerable. That assessment would prove remarkably prescient.

The IRGC’s concern reflected a calculation Tehran had been making for years. The regime understood that openly building a bomb would almost certainly trigger military action from Washington and Jerusalem. Staying just below the threshold, while maintaining strategic ambiguity about how close it really was to weaponization, might generate deterrence without the political and military costs of declaring an arsenal.

The Threshold Strategy and the Axis of Resistance

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This approach worked in tandem with Iran’s regional proxy network. Tehran built a system of non-state armed actors that functioned as a kind of insurance policy: bomb us, and we will do something extreme — close the Strait of Hormuz, for instance. Groups like Hezbollah in Lebanon, Hamas in Gaza, and the Houthis in Yemen could pressure Israel and threaten American bases and allies across the region.

Combined with Iran’s missile and drone arsenal — which we now know was far larger than previously believed — and its nuclear infrastructure hovering tantalizingly close to weapons-grade enrichment, this produced what analysts at the Belfer Center described as a layered deterrence model. It let Tehran expand its influence while minimizing the costs of direct confrontation.

The threshold posture carried another advantage. Iran could use its nuclear progress as a bargaining chip while avoiding the severe isolation that comes with actually building a bomb. By 2023, Iran possessed over 400 kilograms of uranium enriched to 60 percent, requiring only further refinement to weapons-grade purity to construct several warheads — even if the real weaponization process was far more complicated than most media coverage suggested.

But this carefully constructed model rested on assumptions that have now collapsed. Nicole Grajewski, a fellow at the Carnegie Endowment for International Peace, wrote in Foreign Affairs that Tehran wanted the benefits of a nuclear weapon without the actual weapon, and the power of a regional proxy network without the discipline to husband it carefully.

When the Architecture Collapsed

The devastation of that network began well before the current war. Following the October 7 attacks, Israel systematically dismantled Hamas in Gaza and degraded Hezbollah’s capabilities in Lebanon. The fall of Bashar al-Assad’s regime in Syria then severed critical supply routes that had sustained these groups. By the time Washington and Jerusalem launched their joint air campaign in February, the destruction of Iran’s axis of resistance had left it extremely exposed.

More damaging still was the revelation that the threshold position offered no protection whatsoever. As Professor Mohammed Ayoob, a senior fellow at the Center for Global Policy, wrote in The National Interest, remaining a threshold state did not guarantee security. Tehran was attacked anyway, with devastating consequences for its nuclear infrastructure, military facilities, and leadership. Iran had curbed its nuclear ambitions at what now looks like the most inopportune moment imaginable — close enough to a bomb to invite a preventive strike, but not close enough to deter one.

Today the entire architecture of that deterrence strategy lies in ruins. Deterrence cannot be outsourced to proxies when those proxies are dead or incapacitated, and the strategy of getting close to a weapon without crossing the threshold clearly did not work. For Iranian officials surveying the wreckage, an obvious lesson emerges. What separates Iran and Venezuela from the other nations Trump has threatened but never actually attacked — like North Korea or Greenland?

Both either possess nuclear weapons or, in NATO-protected Greenland’s case, are shielded by them.

Lessons From North Korea and Russia

For North Korea’s Kim Jong Un, nuclear weapons are a guarantor of regime security, and he has no intention of giving them up. Despite sanctions in place since 2006, Pyongyang has amassed dozens of warheads and is now qualitatively refining and quantitatively expanding its nuclear forces. Crucially, nobody bombs North Korea.

Instead, they try to bring it to the negotiating table — Kim held three high-profile meetings with President Trump during his first term. By contrast, the highest official the Iranians have sat across from is Vice President JD Vance, who lacks the authority to agree to a deal and must report back to the president.

The lesson is stark. Under Trump, nuclear powers earn Washington’s respect — however begrudging, even toward NATO allies France and Britain — while non-nuclear powers get junior officials who need approval from the adults in the room.

That same lesson has repeated across the world. When Russia invaded Ukraine in February 2022, NATO never came close to intervening directly, for fear of escalation with a nuclear-armed opponent. Moscow waged a brutal war while NATO watched, condemning Russian atrocities, imposing sanctions, and providing intelligence support, but stopping well short of direct military engagement.

The Two-Way Street of Nuclear Fear

That fear of nukes was, and is, a two-way street. Rather than intervene directly, NATO pumped weapons into Ukraine — about 220,000 tons of military assistance in 2025 alone, including systems Putin had previously called red lines: advanced main battle tanks, HIMARS rocket systems, and Storm Shadow missiles. Russia watched it all unfold and was clearly unhappy. Yet despite repeated threats from figures like former Defense Minister Sergei Shoigu, Moscow never bombed the NATO logistics hubs supplying Kyiv.

No missiles smashed into Polish cities. Direct strikes on NATO were relegated to gray-zone tactics — small numbers of cheap decoy drones without warheads — and even those quickly stopped after NATO members vowed to retaliate.

The conclusion is simple. NATO refrained from intervening in Ukraine, and Russia refrained from seriously attacking NATO, because both sides are terrified of nuclear armageddon. Meanwhile Ukraine — which inherited a vast nuclear stockpile at the collapse of the USSR, only to voluntarily surrender all of it — has been bombed continuously for more than four years.

For Tehran, the conclusions are impossible to ignore. Conventional military strength does not deter nuclear powers. International agreements do not deter nuclear powers. Being strategically valuable to the West does not deter nuclear powers. The only thing that reliably deters nuclear powers is other nuclear powers.

The Strategic Bind

Understanding that nuclear weapons are the answer creates its own set of problems. Iran now faces what game theorists would recognize as a strategic bind. Logically, the best move is to build the bomb. Yet pursuing it almost guarantees detection, and detection invites exactly the devastating response Iran is trying to avoid — especially since acquiring a weapon is far harder than many assume.

In 2024 the International Atomic Energy Agency estimated that Iran’s breakout time — the span needed to produce enough weapons-grade fissile material for a single bomb — had fallen to weeks or even days. That was before the 12-Day War and the current campaign, both of which significantly degraded Iran’s technical capabilities. After the war began, the Iran War Room, a website tracking the conflict’s progress, estimated that breakout time had stretched to between one and three months.

But producing fissile material is only the first step. Building a working weapon takes considerably longer. Most analysts assess that, rather than months, Iran would now need at least one to two years to field a deliverable nuclear weapon capable of acting as a genuine threat against its enemies.

That timeline would give Israeli and American intelligence ample opportunity to detect the effort. The surveillance apparatus that tracked Iran’s program before the war remains operational, and when detection comes, Washington and Jerusalem are all but certain to drop enough bombs to make good on Trump’s threat to return the country to the stone age.

Why the Incentives Still Point Toward the Bomb

Despite those risks, the current incentive structure points relentlessly toward weaponization. Iran’s leadership watched North Korea endure worse isolation while building an arsenal. They watched Russia invade Ukraine while NATO held back. They watched weapons flow through Poland to kill Russian soldiers while Moscow refrained from striking NATO territory. The rational calculation, from Tehran’s perspective, increasingly favors accepting the risks of pursuit.

A crude device that could be assembled and tested quickly might not deliver the sophisticated deterrence Iran would prefer, but it would fundamentally alter the strategic environment in the Middle East. Even a single successful test would force Washington and Jerusalem to weigh carefully whether further strikes were worth the risk. For Tehran, that is the best possible outcome — the moment ambiguity hardens into a demonstrated capability, the entire equation changes.

What Comes Next

If Iran manages to build a nuclear weapon — a big if, given the obstacles — the consequences would extend far beyond Tehran’s immediate security. It would show leaders everywhere that, regardless of pressure, building a bomb is the surest way to protect a country. Crown Prince Mohammed bin Salman has stated multiple times that if Iran developed a nuclear bomb, Saudi Arabia would follow as soon as possible. Some analysts believe Pakistan could supply a weapon to Riyadh as part of their long-standing cooperation.

Saudi Arabia would not be alone. Experts expect a proliferation cascade that also includes Turkey and Egypt. In 2019, Turkish President Recep Tayyip Erdogan told members of his AK party that some countries have missiles with nuclear warheads while Turkey is told it cannot, adding that he could not accept this. If Iran goes nuclear, Ankara will almost certainly view it as an opening for its own ambitions.

The UAE and Egypt would likewise seek weapons to preserve the regional balance of power. Some would move faster than others, but once the ball is rolling it will be hard to stop — and not just in the Middle East.

The Global Aftershocks

The shockwaves would reach well beyond the Persian Gulf. An April 2025 poll by the Asan Institute for Policy Studies found that roughly 76 percent of South Koreans want an indigenous nuclear weapons capability — the highest figure the institute has recorded. Fewer than half of respondents believed the United States would use nuclear weapons to defend South Korea if North Korea struck it with nukes.

In Japan, a recent poll found that over 60 percent of people oppose Tokyo possessing a nuclear weapon, yet a senior security adviser to Prime Minister Sanae Takaichi reportedly said Japan should have them. Even as the official insisted there were no government discussions on the matter, the fact that such a suggestion could be aired publicly shows how far the debate has shifted.

Europe is not immune either. Several countries, including Sweden and Poland, might choose to join a nuclear arms race. Both are currently covered by the British and French deterrents, yet Polish President Karol Nawrocki and Jimmie Akesson — leader of the right-wing Sweden Democrats, who prop up the government of Ulf Kristersson — have previously floated developing their own weapons programs. A scramble for independent arsenals remains a worst-case scenario, and the odds of it playing out are extremely low.

But they are not zero.

The Treaty That Was Built for This Moment

If the worst case materialized, the world could face the largest wave of nuclear proliferation since the Cold War. The Treaty on the Non-Proliferation of Nuclear Weapons — which limited the spread of nuclear arms by requiring non-nuclear states to forgo developing them in exchange for access to peaceful nuclear technology and security guarantees from nuclear powers — was designed to prevent exactly this. Yet it has never been tested the way an Iranian bomb would test it.

North Korea violated the treaty and faced consequences, but Pyongyang has limited international connections and minimal economic integration with the global system. Its arsenal threatens primarily South Korea, Japan, and American forces in the region, and it never triggered a cascade because the threat was so contained. Iran is different.

Tehran sits at the crossroads of the Middle East, the Persian Gulf, and Central Asia. It borders regional powers including Turkey and Pakistan, influences events from Lebanon to Yemen, fields proxies across multiple countries, and has demonstrated it can block the Strait of Hormuz, through which 20 percent of global oil and natural gas passes.

An Iranian nuclear weapon would not merely alter Tehran’s security position. It would force every regional power to recalculate its posture, reshape security arrangements across the Middle East, and potentially trigger the very arms race the NPT was built to prevent. The balance of power in one of the world’s most volatile regions would fundamentally shift.

The Bitter Irony

There is a deep irony in all of this. The United States and Israel launched their campaign with the explicit goal of preventing Iran from ever obtaining nuclear weapons. They destroyed facilities, killed scientists, decimated the leadership, and set the program back years. But in doing so, they may have guaranteed the exact outcome they sought to prevent.

Tehran now faces a choice between permanent vulnerability to future strikes and pursuing the one thing seemingly guaranteed to deter military action: nuclear weapons. For Washington and Jerusalem, this creates an impossible dilemma. They cannot accept a nuclear Iran, yet the very tools they used to prevent one have likely only hardened Tehran’s resolve to acquire it.

Another round of strikes might buy time, but it will not change the underlying calculation driving Iran toward weaponization. The open questions now are whether Tehran will actually do it — and whether the world can prevent the cascade of proliferation that would most likely follow.

Presented by

Simon Whistler

Simon Whistler is one of YouTube's most prolific educational creators. WarFronts is his deep dive into military history and conflict analysis.

Frequently Asked Questions

What was Iran’s “threshold” nuclear strategy and why did it fail?

Iran deliberately kept its nuclear program just below weaponization, maintaining strategic ambiguity about how close it truly was to a bomb. The aim was to generate deterrence and preserve a bargaining chip without the costs of openly declaring an arsenal. By 2023 Iran held over 400 kilograms of uranium enriched to 60 percent — close enough to weapons-grade to invite a preventive strike, but not close enough to deter one. When the proxy network underpinning its “layered deterrence” was gutted and Iran was attacked anyway, the threshold strategy was exposed as offering no protection whatsoever.

Did Iran’s leadership ever publicly oppose nuclear weapons?

Yes. Former president Hassan Rouhani recounted Khamenei saying, “We don’t want nuclear weapons,” and describing Iran’s nation and youth as its true nuclear weapon. Khamenei had also issued a fatwa calling nuclear arms haram, or forbidden — a ruling backed by Iranian public opinion. The IRGC, however, had been pressing Khamenei to rescind the fatwa for years, arguing Iran had never been more vulnerable.

What does North Korea’s example teach Tehran about nuclear weapons?

Despite sanctions since 2006, Pyongyang amassed dozens of warheads and nobody bombs it. Kim Jong Un secured three high-profile meetings with President Trump, while Iran was offered only Vice President JD Vance, who lacked authority to conclude a deal. The lesson, from Tehran’s perspective, is that nuclear powers earn Washington’s respect while non-nuclear powers get junior officials who must report back to the adults in the room.

How long would it take Iran to build a deliverable nuclear weapon?

Before the war, the IAEA estimated Iran’s breakout time — producing enough fissile material for one bomb — had fallen to weeks or even days. After the war degraded Iran’s technical capabilities, the Iran War Room estimates it at one to three months for the fissile material alone. Building an actual deliverable weapon would take most analysts’ estimate of at least one to two years, leaving ample time for US and Israeli intelligence to detect the effort and mount another strike.

Which countries might follow Iran into the nuclear club, and why would an Iranian bomb be more destabilizing than North Korea’s?

Saudi Arabia’s Crown Prince Mohammed bin Salman has repeatedly stated Riyadh would follow if Iran goes nuclear, possibly with Pakistani help; Turkey, Egypt, and the UAE are also expected to seek weapons. North Korea triggered no cascade because it is economically isolated and its threat is largely contained. Iran, by contrast, sits at the crossroads of the Middle East, the Persian Gulf, and Central Asia, borders Turkey and Pakistan, fields proxies across the region, and can block the Strait of Hormuz — through which 20 percent of global oil and gas passes — making a full proliferation cascade far more likely.