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Source: Foreign Policy

May 7, 2023

What Most People Get Wrong About the Iran Nuclear Deal
It ensured that even in the worst-case scenario, Iran would be proliferating from a lower baseline.

By Jane Darby Menton, a postdoctoral research scholar at the Berkeley Risk and Security Lab at the University of California, Berkeley.

Five years ago on Monday, then-U.S. President Donald Trump withdrew the United States from the Joint Comprehensive Plan of Action (JCPOA), a 2015 multilateral agreement that imposed restrictions on Iran’s nuclear program. Although both the Trump and Biden administrations promised to find a better solution, the Iran nuclear crisis has only gotten worse. Economic pressure and external sabotage have not stopped Tehran from steadily increasing its uranium enrichment capabilities. Today, the regime is only weeks, if not days, away from the ability to produce enough fissile material for a nuclear weapon, should it choose to take that step.

Although restoring the JCPOA has become increasingly implausible, understanding how it worked—and what has been lost—is essential for future global nonproliferation efforts.

Most discussions about the Iran deal focus on the wrong things. Critics argue that it was too permissive because it recognized Iran’s right to enrich uranium; too limited because it included sunset clauses; and too narrow because it failed to address other troubling activities, such as Iran’s ballistic missile program and its support for violent groups in the Middle East. Defenders, meanwhile, emphasize that the deal allowed for unprecedented international monitoring and verification of Iran’s nuclear program. Both camps devote less attention to the agreement’s impact on Iran’s actual nuclear capabilities.

As recent events demonstrate, diplomacy cannot stop states from subsequently expelling inspectors, unplugging monitoring cameras, or resuming prohibited activities. Those who dismiss the JCPOA as a weak agreement, however, tend to overlook what made it credible and valuable from a nonproliferation standpoint. This has warped the public debate. Instead of dwelling on the JCPOA’s more reversible features, we should focus on what made it truly unique. It is unusual for diplomacy to succeed in rolling back a more advanced nuclear program. And somehow, the JCPOA managed to do just that.

Then-U.S. Secretary of State John Kerry leaves after addressing a news conference on Iran nuclear talks in Vienna, Austria, on July 14, 2015. CARLOS BARRIA/AFP VIA GETTY IMAGES

Donald Trump speaks at a protest against the Iran nuclear deal in front of the U.S. Capitol in Washington on Sept. 9, 2015. LINDA DAVIDSON/THE WASHINGTON POST VIA GETTY IMAGES

Proliferation is often presented as a binary: States either have nuclear weapons, or they do not. That’s why conversations about proliferation tend to revolve around “breakout,” or the time a state needs to amass sufficient fissile material for a single nuclear device. Roughly speaking, this translates to either 25 kilograms of weapons-grade uranium or 4 kilograms of separated plutonium. Breakout estimates consider multiple factors, including how much fissile material states possess, how quickly they can produce more, and how long it would take them to bring existing stockpiles up to weapons-grade.

On its own, however, breakout is a somewhat misleading benchmark. States need more than one nuclear device to establish a credible deterrent, and packaging fissile material into deliverable warheads involves additional steps and technical bottlenecks. This is why a more holistic assessment of nuclear capabilities is valuable from the standpoint of risk reduction.

As scholars such as Tristan Volpe have pointed out, there is a spectrum of latent nuclear capabilities. Tehran went into the JCPOA negotiations on the advanced side of that spectrum, with multiple active nuclear sites, including hardened facilities designed to withstand military strikes. Its scientists had already mastered key elements of the fuel cycle and recovered from setbacks such as the Stuxnet virus, which sabotaged the centrifuges they use for uranium enrichment. As then-U.S. Director of National Intelligence James Clapper testified in 2016, “[Iran] does not face any insurmountable technical barriers to producing a nuclear weapon.” (By comparison, when Libya voluntarily disarmed in 2003, its nuclear program was small and largely ineffective.)

The JCPOA extended Iran’s breakout time from a few months to a year, but more importantly, it ensured that in the worst-case scenario, Iran would be proliferating from a lower baseline.

The deal rolled back Iran’s nuclear capabilities in two main ways. The first was by removing stockpiles of fissile material. Eliminating materials automatically puts time back on the clock, because states cannot use what they do not have. Since the consequences are immediate, stockpile reductions are valuable confidence-building measures. Under the interim nuclear agreement established in 2013, a precursor to the JCPOA, Tehran demonstrated its commitment to diplomacy by dismantling reserves of medium-enriched uranium. The JCPOA then required Tehran to cut stockpiles of low-enriched uranium from roughly 7,000 kilograms to 300.

The JCPOA extended Iran’s breakout time from a few months to a year, but more importantly, it ensured that in the worst-case scenario, Iran would be proliferating from a lower baseline.

The second way was by impeding future activities. Although the JCPOA recognized Iran’s uranium enrichment program, it restricted the number and kind of centrifuges the regime could use and capped enrichment levels at 3.67 percent for 15 years. (Highly enriched uranium, which is required for nuclear weapons, involves enrichment to 90 percent.) Tehran dismantled various centrifuge cascades and agreed to store decommissioned equipment and other enrichment-related infrastructure in facilities that would be subject to continuous International Atomic Energy Agency (IAEA) monitoring. Negotiators also targeted processes that are crucial for weaponization. This is why the deal included a moratorium on uranium and plutonium metallurgy, which is used to produce bomb components, and a ban on research pertaining to nuclear explosives modeling and neutron initiation. The deal also curbed Iran’s capabilities by prioritizing its most concerning nuclear facilities. For example, the JCPOA did not allow uranium enrichment to continue at the Fordow fuel enrichment plant, which, at least at the time, was less vulnerable to attack than the Natanz facility.

In a photo released by the Islamic Republic News Agency, unidentified International Atomic Energy Agency (IAEA) inspectors and Iranian technicians work at the nuclear research center in Natanz, Iran, on Jan. 20, 2014.KAZEM GHANE/IRNA/AFP VIA GETTY IMAGES

Part of the JCPOA’s strength came from Iran accepting limits that are harder to reverse. This included surrendering access to equipment and materials. For example, Iran was obliged to export spent fuel—which can be used to source plutonium for a weapons program—from its research reactors. Other concessions had even longer-lasting effects. Limits that affect nuclear facilities’ physical infrastructure are particularly hard to undo. Some nuclear reactors pose a greater proliferation risk than others, either because they produce more weapons-useable material or are less vulnerable to export controls and other supply-side disruptions. Although most conversations about Iran focus on uranium enrichment, the JCPOA used reactor design to effectively block the plutonium pathway to proliferation.

Without these alterations, the reactor would have generated enough plutonium in its spent fuel for one to two bombs each year once it came online.

Under the deal, the international community promised to help convert the heavy-water research reactor in the Iranian city of Arak into a design that would be more conducive to civilian scientific work and less conducive to a weapons program. Without these alterations, the reactor would have generated enough plutonium in its spent fuel for one to two bombs each year once it came online. Since 2019, Tehran has accelerated uranium enrichment, but at least for now, the benefits of a more efficient research reactor have translated into a more durable check on plutonium production. Alone, this will not prevent proliferation, but it will constrain Iran’s future capabilities.

Although more technical risk-reduction measures such as those in the JCPOA receive less public attention, they have long played—and should continue to play—an important role in U.S. nonproliferation policy. For decades, diplomats have used nuclear cooperation agreements to influence reactor design, incentivize adherence to safeguards, and induce greater reliance on the globalized nuclear marketplace.

The now defunct Agreed Framework between Washington and Pyongyang attests to the lingering impact of such concessions. An underappreciated consequence of that deal is that it permanently set back North Korea’s ability to produce plutonium. Under the agreement, the United States—with help from Japan and South Korea—promised to build two “proliferation proof” light-water nuclear reactors if North Korea halted construction on two graphite-moderated reactors, which are better at generating plutonium than electricity. Over time, those frozen construction sites became unsalvageable. (The light-water nuclear reactor power plants, meanwhile, never came to fruition.) North Korea was still able to build a nuclear arsenal, but even today, it can only produce significant amounts of plutonium for its weapons program at one site in Yongbyon.

Iranian students form a human chain around a uranium conversion facility, demonstrating their support of Iran’s decision to reopen the plant and urging the state to resume enrichment, east of Isfahan, Iran, on Aug. 16, 2005.ATTA KENARE/AFP VIA GETTY IMAGES

Of course, nonproliferation agreements are imperfect. Stockpiles can be rebuilt, as Tehran demonstrated after the Trump administration’s withdrawal. According to a February 2023 IAEA report, Iran now has roughly 87 kilograms of 60 percent enriched uranium and about 435 kilograms of 20 percent enriched uranium. The stockpiles that Iran dismantled under the JCPOA were not as close to weapons grade; it only began amassing 60 percent enriched uranium in 2021. And even intrusive monitoring regimes cannot guarantee that states will not continue some activities in secret. North Korea had a covert uranium enrichment program while the Agreed Framework was in force, and it likely pursued illicit weaponization research. But the imperative of concealment stymies progress, especially under agreements that include stringent monitoring. States cannot go as far, as fast, if they want to avoid detection.

Defenders are not off base in praising the comprehensiveness of the Iran deal’s monitoring and verification regime. Nor are skeptics wrong about some of the JCPOA’s limitations, including its failure to address Iran’s other concerning behaviors at home and abroad.

But exclusively focusing on questions of scope and duration perpetuates the myth of a better deal—the idea that more pressure or more diplomacy might yield a better solution to the Iran nuclear crisis. Even the Biden administration was initially enamored with the notion of a “longer and stronger” agreement with Iran. From a risk-reduction standpoint, however, the JCPOA was valuable because it directly impacted Tehran’s present and future nuclear capabilities. What the JCPOA briefly achieved was a safer status quo by rolling back Iran’s nuclear program and institutionalizing mechanisms to contain the regime at this lower level. Iran’s compliance with the deal over any period was designed to have lingering effects on the size of any future arsenal, weaponization timelines, and Tehran’s ability to cross the nuclear threshold undetected.

Nonproliferation gets harder as nuclear programs advance. There are many reasons for this: path-dependency, vested interests, and the irreversibility of scientific knowledge and experience. Nuclear sophistication may also have diminishing returns in diplomacy—as Volpe has argued, states with highly advanced programs suffer from a credibility gap at the negotiating table. This is concerning, as Tehran seems to believe that drawing closer to the brink will give it more diplomatic leverage. The JCPOA was already an unlikely achievement given the status of Iran’s nuclear program back in 2015. These problems will only multiply as the regime becomes more capable.

In the past five years, the prospects of peacefully resolving the Iran nuclear crisis have gone from bad to worse.

Tehran is once again on the precipice of breakout, and addressing proliferation concerns through diplomacy has only gotten harder. In addition to the technical hurdles, political conditions have deteriorated significantly. Trump’s withdrawal undermined confidence in the reliability of U.S. commitments. Engaging with Iran has only gotten more complicated since 2021, when the Hassan Rouhani government was replaced by the hard-line Ebrahim Raisi administration, which is more skeptical of diplomacy with the West. Meanwhile, consensus among the rest of the deal’s original signatories (the United States, the United Kingdom, France, China, Russia, Germany, and the European Union) has eroded, and Iran has deepened and diversified its ties with other autocracies, including Russia.

At this point, it is probably too late for the JCPOA. Still, the deal demonstrated that it is possible to negotiate meaningful limits on advanced nuclear programs. Cultivating broader awareness about how this agreement worked should at least inform future debates over nonproliferation strategy and nuclear risk reduction with Iran and other potential proliferators. U.S. National Security Advisor Jake Sullivan’s recent comments about seeking “a diplomatically brokered outcome that puts Iran’s nuclear program back in the box” indicate that Washington is again taking nuclear capabilities seriously. On the anniversary of the Trump administration’s withdrawal from the JCPOA, we should not let the quixotic quest for better deals continue to eclipse the practical benefits of curbing and containing dangerous nuclear programs.

Jane Darby Menton is a postdoctoral research scholar at the Berkeley Risk and Security Lab at the University of California, Berkeley. Twitter: @JDMenton

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