Even as a ceasefire has ended the so-called twelve-day war between Israel and Iran, the dust has yet to settle. The slow-moving crisis around Iran’s potential nuclear weapons ambitions is escalating in ways that could have far-reaching consequences—from an increased likelihood of further conflict to lasting damage to the international institutions critical to preventing the spread of nuclear weapons.

Iran’s New Nuclear Law

Last week, Iran’s president signed a law mandating that all cooperation with the International Atomic Energy Agency (IAEA) be suspended. This measure marks a new period of acrimonious relations in an already turbulent relationship between Tehran and the IAEA. Depending on implementation, the law could prevent the IAEA from carrying out its mandate to verify Iran’s compliance with its nonproliferation safeguards agreement unless and until certain conditions are met.

In practice, this means the international community will have no authoritative eyes on the Iranian nuclear program for the foreseeable future. Although individual countries’ intelligence services will continue to scrutinize Iran’s activities, they are not an adequate substitute for the IAEA’s independent, on-the-ground assessments.

Barring IAEA inspections carries two risks for the unfolding Iranian nuclear crisis. First, the absence of agency monitoring will create gaps in accounting for Iran’s nuclear materials and equipment at a time when accountancy could not be more important to reassuring the world that Tehran is not seeking nuclear weapons. As Iran assesses the damage sustained from the U.S. and Israeli strikes against its key nuclear facilities, it will have an easier job hiding any salvaged assets necessary for a weapons program than if IAEA inspections were ongoing. Second, intelligence disputes around Iran’s nuclear activities will likely continue, leading to fractures in the international community—and potentially even within individual states—on how to respond, especially if any intelligence reports point to certain activities as evidence that Iran is sprinting for a bomb.

Combined, the potential for misperception and miscalculation caused by less visibility into Iran’s nuclear program increases the likelihood of resumed hostilities.

Undermining the Nonproliferation Regime

More broadly, this crisis now has greater potential to cause far-reaching damage to nonproliferation institutions. The Israeli and U.S. strikes themselves undermined the legal, economic, and diplomatic means—including President Donald Trump’s administration’s own negotiations with Tehran that had been ongoing since April—for resolving the Iran nuclear issue peacefully. Although the attacks aimed to prevent Tehran from developing the bomb, they very well could have the opposite effect, merely delaying Iranian nuclear acquisition while diminishing the efficacy of tools that prevent other states from following suit.

Iran’s response to the strikes stands to inflict further damage. Its narrative around the new law—namely that the IAEA bears culpability for the strikes—may resonate with other countries sympathetic to its plight. These countries may perceive the law as a justifiable response, given that Iran’s safeguarded and ostensibly civilian nuclear facilities were attacked by not one but two nuclear-armed states. This very concerning precedent is only made worse by Israel possessing nuclear weapons outside of international nonproliferation frameworks. Of course, this episode does not exist in a vacuum and larger dynamics may be informing the Iranian narrative. Nevertheless, Iran’s actions risk undermining the technical authority, credibility, and independence of the IAEA as the world’s “nuclear watchdog.” If the IAEA becomes more widely perceived as a tool of the big powers, it will have a harder time carrying out its mission to detect cheating by any state on its nonproliferation obligations and provide evidence to hold them accountable.

Iranian officials maintain that their new law does not violate these obligations, that it merely suspends (rather than terminates) its required IAEA safeguards agreement. But this measure could very well be a prelude to an even bigger escalation: Iran’s withdrawal from the Nuclear Non-Proliferation Treaty (NPT), the primary international legal structure that prohibits the spread of nuclear weapons.

Numerous Iranian officials have pointed to this possibility in the wake of the Israeli and especially U.S. strikes. Abbas Araghchi, Iran’s foreign minister, stated plainly that the U.S. strike “has severely questioned the NPT, shaken the non-proliferation regime, and will have adverse consequences for international security.”

Any NPT member can withdraw from the treaty should it deem that “extraordinary events” have jeopardized its supreme national interests. Iran has a fairly straightforward case for invoking this withdrawal clause by pointing to the Israeli and U.S. strikes against its nuclear program as an extreme threat to its national security. And it could expect to find a sympathetic ear in—or at least a lack of pushback from—many capitals around the world that opposed the strikes.

While exiting the treaty would not necessarily be an indication of Tehran’s intent to develop nuclear weapons, it would eliminate the international legal requirement that Iran maintain a safeguards agreement with and submit its nuclear activities for regular monitoring by the IAEA. This would make it exceedingly more difficult to reliably detect whether Iran had made such a decision to go nuclear in the future.

Iranian NPT withdrawal could also diminish other states’ confidence in the nonproliferation regime. On the one hand, states may doubt its ability to constrain any would-be proliferator, let alone Iran’s nuclear ambitions. On the other hand, they may question its ability to protect legitimate nuclear programs from attack. This disillusionment with the system could lead to further defections, eroding the treaty’s efficacy and fracturing an important foundation of international peace and security. Diminishing the credibility of the treaty would attenuate multilateral efforts to prevent the spread of nuclear weapons, could drive more states to take military counterproliferation actions, and at worst, could spur a proliferation domino. Saudi Arabia, for example, has already said it will develop nuclear weapons if Iran does, which could in turn prompt others in the region to do the same.  

Avoiding the Worst Case

How can the international community best address these challenges, both to deescalate the Iranian nuclear crisis and forestall any lasting damage to broader efforts to prevent proliferation?

One of the greatest challenges for any hope of a diplomatic resolution will be securing a credible U.S. and Israeli commitment not to carry out further attacks on Iran. If Iran does not believe that its compliance with any future deal would preclude such attacks, it would have few incentives to negotiate. U.S. and Israeli decisionmakers will need to be convinced that the stakes are now greater than just the immediate future of Iran’s nuclear program. There are no easy answers here.

Yet, even if opposed to the Israeli and U.S. strikes, states should counter Iran’s narrative that the IAEA is to blame and refrain from giving any rhetorical support to Iran’s suspension of cooperation with the agency. They should continue to recognize and reiterate the independence and credibility of the IAEA as well as its centrality to the global nonproliferation order. States such as Brazil, Egypt, and South Africa that do not play a traditional role in the Iranian nuclear issue but have notable roles in the nonproliferation order may be particularly well-suited to this task.

These states, along with key regional players, should also open channels directly with Tehran to reiterate the importance of fully cooperating with the IAEA. They should emphasize that the lack of international monitoring poses substantial risks to Iran’s own security. It fuels the potential for miscalculation around any Iranian nuclear activity that could lead to worst-case assumptions about Tehran’s intent and additional military strikes on Iranian territory.

If Iran decides to withdraw from the NPT, it must give three months’ formal notice. Practically, this would kickstart a new phase of diplomacy and pressure, creating a last-ditch chance to get Iran to the negotiation table. It is not clear that Iranian officials will view the United States as a credible negotiating partner, though they presumably see Washington’s agreement as indispensable. Here, European leaders could play a greater role in diplomacy to keep Iran in the treaty, constrain further Israeli action, and prevent a broader conflict.

Berlin, London, and Paris should begin gaming out now how they can take the reins of such high-stakes diplomacy. One key piece will be finding a meaningful way for Iran to credibly demonstrate that it is not seeking nuclear weapons—for example, by shipping out at least some of its stockpile of highly enriched uranium. The other key piece will be persuading the United States and Israel to offer credible assurances that they will cease military action if Iran complies—for example, through political commitments contingent on Iran’s continued commitment to the NPT and its nonproliferation obligations—and holding them accountable to these assurances.

While certainly no easy feat, these tasks could not be more urgent. Failure to arrest this looming crisis increases the likelihood of not only an Iran determined to develop nuclear weapons, but also additional military strikes and perhaps all-out war. More broadly, it also stands to erode the key institutions that prevent the spread of the world’s most dangerous weapons, paving the way for an exceedingly perilous future.

Correction: The sentence describing the implementation of the law has been edited to better reflect the clarity of the conditions.