In the months since Israel and the United States’ 12-day war with Iran in June, analysts and intelligence agencies have widely debated the extent of the damage to the Iranian nuclear program and regime. It is still unclear how much of Iran’s nuclear infrastructure has survived and how quickly, if at all, it can be reconstituted. On a strategic level, however, the effect of the war is indisputable: it marks the eclipse of a nuclear strategy that the Islamic Republic had pursued, often successfully, since the 1980s.
For decades, Iran was the quintessential nuclear hedger. It sought the know-how and technology to weaponize its nuclear program but stopped short of doing so for political reasons. This threshold strategy was successful, at least for a time. Although both Israel and the United States tried to continually delay the nuclear program through sabotage and targeted assassinations, neither country overtly struck Iran’s nuclear facilities. Then, in 2015, with the signing of the Joint Comprehensive Plan of Action (JCPOA), it seemed as if the regime’s gamble had paid off: Iran received much-needed sanctions relief in exchange for accepting restrictions on its program. The threat created by Iran’s hedging, combined with the second Obama administration’s desire to find a comprehensive diplomatic solution, resulted in successful negotiation of the landmark deal that pushed Iran’s program much further away from a bomb.
But since the 12-day war, that strategy lies in tatters. U.S. and Israeli airstrikes caused substantial damage to key facilities at Natanz, Fordow, and Isfahan and crippled Iran’s military leadership structure. Iran underestimated Washington’s willingness to support Israeli military action and join the campaign itself. Today, Iran finds itself vulnerable to existential territorial attack and regime change efforts, with a bomb likely far out of reach and its negotiating position with the West weaker than ever before.
The failure of Iran as a threshold nuclear power vindicates the strategy of another U.S. adversary: North Korea. In contrast to Tehran, Pyongyang largely avoided delays in weaponizing its program; it made steady progress toward a bomb, using periodic engagement to test U.S. resolve over possible agreements, routinely relied on feints and stalling tactics, and weathered tremendous diplomatic and economic pressure along the way. When diplomacy broke down, North Korea rapidly advanced its program so its Kim regime was prepared to approach any future engagement from a position of greater strength. As Supreme Leader Ali Khamenei attempts to regroup in Iran, North Korean leader Kim Jong Un, with one of the world’s most rapidly expanding and diversifying arsenals and strategic partners in Beijing and Moscow, looms as an example of what could have been. For would-be proliferator states, the lessons are dangerously clear: do not wait to get the bomb, assume major powers will attack, and do not trust that diplomacy is within reach. In other words, be like Kim, not like Khamenei.
MISSED THE MOMENT
As early as the 1970s, Tehran possessed the necessary ambition and expertise to expand its nuclear energy program for potential military purposes. The program had begun two decades earlier under Mohammed Reza Shah Pahlavi and Iran joined the Nuclear Nonproliferation Treaty (NPT) in 1970. During the Iran-Iraq War in the 1980s, the Islamic Republic began covert exploration of more sensitive technologies, such as uranium enrichment, and continued to gain expertise with the assistance of third countries. Beginning in 1989 the regime formulated the so-called AMAD plan, which established a roadmap for the theoretical and engineering work required to weaponize once the country had enriched enough uranium for a bomb.
But Iran did not cross the weaponization threshold. It stopped short for political, rather than technical, reasons: after Iran’s secret nuclear activities were exposed at the beginning of the twenty-first century, Iranian leaders iced the AMAD plan, preferring to trade away its pursuit of a bomb in exchange for economic and diplomatic relief. They continued to conclude that crossing the threshold as a member of the NPT, despite heightened U.S. military presence and freedom to act in the Middle East, was not in Iran’s security and strategic interests. Nonetheless, Iran retained—at enormous expense—the technical expertise, bureaucratic organs, and industrial infrastructure needed to advance civilian nuclear research, medical isotope production, and electricity generation and repurpose it for military use if it were to ever choose to do so. The regime wagered that this threshold program would serve three geopolitical purposes: it would give Iran the ability to quickly develop a bomb if an existential threat appeared imminent; it would deter a military attack from Israel or the United States by keeping both countries uncertain about how close Tehran was to building a bomb; and it would provide leverage with its antagonists in the West by using limits on the program as a bargaining chip for relief from punishing economic sanctions.
For the nearly two decades since pausing the AMAD plan, Iran voluntarily stopped short of crossing the weapons line. Even as Iran’s nuclear scientists envisioned an initial arsenal of five weapons, Tehran’s political leaders were ambivalent about whether the aim of the country’s program was to achieve a nuclear weapons arsenal or to trade away large chunks of it for economic and political concessions. They were, however, largely convinced that walking just up to the weaponization threshold would safeguard the nation from existential attack. After years of brinkmanship with the George W. Bush and first Obama administrations, they seemed to be proved right with the conclusion of the JCPOA, which allowed Tehran to trade away parts of the program to bolster Iran’s reputation and economy.
But the JCPOA did not mandate that future U.S. administrations adhere to the agreement and under the first Trump administration, the United States withdrew, in 2018. After this perceived betrayal, Iran began stockpiling large quantities of enriched uranium, including at levels of purity much closer to that required for a nuclear bomb. These actions created negotiating leverage for a future deal but also a potential insurance policy against the unpredictable first Trump administration and Israel, which made little secret of its desire to attack Iran. The targeted killing of the Iranian general Qasem Soleimani by the United States in 2020 likely calcified these concerns in the minds of Iran’s leaders.
After inconclusive indirect talks during the Biden administration and Israel’s increasingly offensive regional military actions in the wake of Hamas’s brazen October 7 attacks, Iran, according to some estimates, crept to within days of being able to enrich enough uranium for a bomb. Finally, with President Donald Trump’s return to the White House in 2025, the potential for a U.S.-backed Israeli attack on Iran suddenly became a reality and the flaws of the threshold strategy were laid bare. In June, Tehran paid the price for wavering, and the United States, for the first time in the nuclear era, struck the nuclear facilities of another state. Had Iran crossed the nuclear Rubicon back in 2003, the United States might well have avoided such a direct confrontation, which would have invited all the risks of attacking a nuclear-armed adversary.
NORTH STAR
Here’s where the contrasting case of North Korea becomes instructive. In the 1960s, Pyongyang, facing a conventionally superior U.S. ally South Korea on its border under a condition of armistice, not peace, initiated a program focused on nuclear energy. But throughout the Cold War, it sought support to develop a nuclear weapon from the Soviet Union and China. North Korea sparked a crisis in the early 1990s by refusing to cooperate with the International Atomic Energy Agency (IAEA) to address its incomplete declarations regarding its nuclear program, leading to international suspicion that it was conducting illicit weapons-related activities. The United States seriously contemplated striking North Korea’s Yongbyon reactor in 1993, even drawing up military plans to attack the site with penetrating munitions delivered by stealth bombers. But the Clinton administration aborted the idea out of fear that an attack could result in retaliation against South Korea and a broader war, and instead sought a diplomatic solution. The result was the 1994 Agreed Framework, which required that North Korea freeze the construction of nuclear reactors suspected of being used in weapons production and placed the country’s existing plutonium production capabilities under the IAEA inspection regime. In return, the United States and other partners agreed to provide nuclear reactors less capable of use for nuclear weapons work and to supply fuel to address the energy needs cited by North Korean leader Kim Il Sung as the rationale for building nuclear reactors.
But Pyongyang approached the Agreed Framework (and every subsequent nuclear diplomatic initiative) disingenuously, often as a stalling tactic, while successive members of the Kim dynasty prioritized the nuclear weapons program and devoted as many resources as possible to pursuing a nuclear weapons capability. Unlike Iran,North Korea showed little interest in trading meaningful chunks of its program for sanctions reliefbefore obtaining a nuclear weapon once the Agreed Framework fell apart in 2003. When foreign intelligence or international monitors would reveal an undeclared activity during the course of nuclear diplomacy, North Korea would ratchet up pressure by testing missiles or provoking Seoul. When the United States and its allies threatened reprisal or attack, as in the Yongbyon episode, or after the United States placed bombers on alert in response to North Korea’s restarting facilities shuttered under the Agreed Framework, its breaching of NPT obligations, and its withdrawal from the treaty in 2003, Kim Il Sung and, later, Kim Jong Il pivoted toward diplomacy, deceitfully promising to halt weapons-related activities and engage in good-faith diplomacy. All the while, North Korea continually advanced its nuclear infrastructure, weapons designs, and missile programs, often accelerating work between high-profile moments of engagement with the United States.
Today, Kim Jong Un is sitting on one of the world’s fastest growing nuclear arsenals, with a variety of options for striking South Korea and Japan, including possible tactical nuclear weapons, and long-range missiles to target the United States.With this arsenal, the North Korean leader is more confident in his ability to deter a U.S. or South Korean attack or attempt at regime change. Iran’s situation could not be more different. With his military and nuclear program at least temporarily shattered and his regime fragile, Khamenei has paid the price for failing to secure nuclear insurance. Iran’s hardliners may feel that failing to weaponize and pursuing diplomacy with great powers made Iran vulnerable to the kind of attacks North Korea’s decisive proliferation strategy has helped it avoid.
GOING DARK
As the experience of Iran has shown, a threshold proliferation strategy not only appears to be insufficient to deter counterproliferators; it may instead increase their willingness to preemptively attack the program as they remain in the dark about the actual state of weaponization. Maintaining the technical basis to be able to quickly develop nuclear weapons—what nuclear strategists call latency—does not deter nearly as effectively as actually having nuclear capabilities. On the contrary, a state with a latent nuclear program presents a ripe target for adversaries and counterproliferators seeking to prevent weaponization who may be tempted to act swiftly before the window to do so closes and the state can plausibly threaten nuclear retaliation.
Israel saw such a window in June and took full advantage, executing a strike Netanyahu and the Israeli right had dreamed of for years. For aspiring nuclear powers, the lesson was clear: advertising and brandishing a nuclear program against far stronger military powers, without yet having a nuclear bomb to deter a preventive attack, is a risky game. Would-be proliferators will be unlikely to repeat this mistake. In addition to not postponing weaponization as long as Iran did, potential proliferators such as Poland, Saudi Arabia, South Korea, Ukraine, and the United Arab Emirates will likely prioritize higher operational security and will attempt to hide their programs from counterproliferators more effectively than Iran did. Future proliferators will likely seek to weaponize as rapidly as they can and will do so covertly.
Unlike Iran’s program, which could not remain covert over the long hedging period and the on-and-off diplomatic process during which Tehran was forced to be more transparent about its activities, these potential programs may be revealed not in their pre-weaponization stages as a point of diplomatic leverage, but only after a nuclear weapon is announced—or tested. Future proliferators may thus be willing to sacrifice speed for security by driving their program fully underground, repurposing what they can from their civilian nuclear industry and technology. Such an approach may be easier for tightly closed regimes than for democracies. Nevertheless, it is possible even for open democracies to have small, effective covert weapons programs—India, allegedly Israel, and South Africa all undertook covert weaponization efforts. Proliferators, including democracies, may be willing to accept the eventual international opprobrium that comes with violating or withdrawing from nonproliferation accords in the name of national security.
Take the case of Bashar al-Assad’s Syria. In the first decade of the twenty-first century, as Iran paused the AMAD plan, Syria rushed to build, and nearly completed, a covert nuclear weapons program. But in 2007, Israeli intelligence serendipitously stumbled on evidence of a Syrian nuclear reactor—a miniature replica of North Korea’s Yongbyon facility—that was housed in a nondescript, aboveground complex in the hinterland near the Euphrates River. With the reactor potentially just weeks away from being fueled (after which it would have been environmentally hazardous to attack), Israel leveled it with airstrikes. Still, the episode provided a stark lesson in covert programs. Despite being high on the West’s nuclear proliferation watchlist, Syria was nonetheless able to maintain impressive operational security for an aboveground nuclear reactor. Only a determined intelligence effort—and a lot of good luck—uncovered the nuclear weapons program. Even if they forswear a North Korean rush to the bomb, future nuclear proliferators are more likely to look to the covert Syrian model than to the more transparent Iranian one.
FINAL OFFER
In addition to spelling the end of the threshold nuclear strategy, the 12-day war will likely have another important consequence. It will make diplomacy with future aspiring nuclear weapons states exceptionally difficult. In the case of Iran, hardliners may now have greater power within the regime and more influence with the supreme leader. They can also convincingly portray the United States and Israel, which struck as Tehran was engaged in talks with Washington, as incapable of and unwilling to find a diplomatic path forward. Indeed, Washington and Tehran now face what the scholar James Fearon has characterized as a “commitment problem.” Both parties may prefer a diplomatic outcome but have strong incentives to avoid negotiations, especially since each side has little trust in the other and assumes it will renege on any future deal. In the United States, fierce polarization will continue to stand in the way of a suitable, bipartisan replacement for the JCPOA.
The supreme leader did not emerge from the war trusting the United States or the P5+1—the group of permanent UN Security Council countries party to the 2015 deal. Instead, he may now believe that the only insurance policy that Iran’s adversaries will honor is a nuclear weapon. He will also likely want to pursue any future negotiations from a position of strength. As France, Germany, and the United Kingdom pursue the reimposition of “snapback” UN sanctions in response to Iran’s noncompliance with its nuclear commitments, the Majlis, Iran’s parliament, is considering legislation to recommend withdrawal from the NPT, echoing the crucial step taken by North Korea in its path to a bomb two decades ago.
U.S. policymakers can still discourage would-be proliferators from pursuing a bomb. Important pillars of American nonproliferation policy have stood the test of time through even the most challenging days of the Cold War and after. Remaining committed to, and enhancing, the United States’ extended deterrence architecture can reassure U.S. allies and partners in Europe and Asia so they do not seek the security blanket of their own nuclear bomb—and invite dangerous attacks on themselves by trying. U.S. officials should emphasize and clarify the costs of pursuing a nuclear weapon to any would-be proliferator, including by cutting off military aid, ceasing nuclear-related trade, levying sanctions and threatening military action. And most important, senior leaders should acknowledge and respect the impressive record of the NPT and the nonproliferation regime: that only nine states possess nuclear weapons, not the 25 that U.S. President John F. Kennedy once predicted, is not the result of blind luck. It is the product of decades of presidential-level attention during the Cold War, when nuclear policy was a matter of grand strategy and not an area of specialization, and strong and consistent nonproliferation diplomacy was prioritized in the U.S. foreign policy machine.
But a United States threatening to upend 80 years of largely successful nonproliferation policy practice and experience is creating incentives for allies and adversaries alike to look for their own nuclear insurance policies. The 12-day war will do nothing to disabuse them of that notion. For future would-be proliferators, relying on the United States to deliver on the promise of a deal like the one it signed with Iran in 2015 looks like a bad bet. Kim Jong Il eventually concluded that the risks of dealing with the United States, and the chaotic U.S. system, was not worth the benefit. His son doubled down on this view. Iranian officials may have assumed that Trump would pursue diplomacy more aggressively during his second term, as his administration’s approach to Iran in the spring of 2025 seemed to indicate. But that hope ended abruptly in June, with the destruction of the core facilities that had brought Iran closer than ever to the weapons threshold.
Even after this severe setback, Iran’s technical advances and knowledge base, and the substantial amounts of nuclear material it had previously amassed, probably remain. Tehran may yet find itself with an opportunity for a do-over, and if it does, it may well take the North Korean approach and not stop until it gets to a bomb. In doing so, it may find its own path to an insurance policy for a new, chaotic nuclear age. Paradoxically Washington’s military action against Iran’s nuclear program may have hastened, hardened, and hidden the march of would-be proliferators toward the bomb.
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