President-elect Donald Trump is retaking office at an inflection point in Iranian nuclear policy. After long denying any interest in nuclear weapons, Iranian officials are now publicly debating the security value of a nuclear deterrent and threatening to pursue nuclear weapons if attacked. This shift in nuclear policy, along with the technical advances that have brought Iran to the threshold of nuclear weapons, poses a serious proliferation challenge that the Trump administration will need to confront immediately upon taking office.
Despite the increasing risk that Iran will weaponize its nuclear program, Iranian President Masoud Pezeshkian continues to emphasize Tehran’s interest in a deal and willingness to negotiate with the incoming U.S. President . Trump, too, appears to have acknowledged the necessity of reaching a nuclear deal with Iran in his second term, even though he withdrew the United States from the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), in May 2018 despite Iran’s compliance. In a September press conference, Trump said that the United States has to “make a deal” with Iran because the “consequences are impossible” if the United States fails to do so.
Even if the political will to negotiate exists on both sides, an agreement is far from assured. Iran’s nuclear program is technically more complex than when the JCPOA was negotiated. Furthermore, Iran’s attempt to use its nuclear weapons threshold status to deter further attacks ties the nuclear program and the prospects for diplomacy to the regional security situation, which is deteriorating. Iran is unlikely to accept significant restrictions on its nuclear program while Israel poses an imminent military threat and its “axis of resistance” is severely weakened through the degradation of key regional allies such as Lebanese Hezbollah and Hamas, as well as the sudden departure of Syrian President Bashar al-Assad. The Trump administration will need to take these factors into account as it determines its Iran strategy.
A New Nuclear Reality in Iran
Iran’s nuclear program has changed fundamentally since negotiations on the 2015 nuclear deal. The Trump administration’s Iran strategy will need to consider Iran’s nuclear advances as it determines what is necessary for a new nuclear agreement to block Iran’s pathways to nuclear weapons and how Iran’s recent threats to weaponize its nuclear program affect the U.S. approach to diplomacy and pressure.
Any new agreement, whether a limited, interim accord or a comprehensive nuclear deal, will need to take into account Iran’s new capabilities. Three areas in particular will affect negotiations.
New Nuclear Knowledge. First, the knowledge Iran has gained from expanding its nuclear program over the past several years cannot be reversed and has altered the pathways available to Iran if the decision is made to weaponize.
When Iran began breaching the JCPOA’s limits in May 2019, a year after the U.S. had ceased complying, it initially focused on resuming activities that had been successfully halted by the nuclear deal. For example, it began exceeding the JCPOA’s stockpile limit of 200 kilograms of low-enriched uranium (defined in the JCPOA as enriched up to 3.67 percent) and increasing enrichment levels to 5 percent. These breaches were troubling but had limited impact on proliferation risk and did not result in Iran acquiring new, irreversible knowledge.
However, beginning in late 2020, Iran began to invest in new nuclear capabilities, including beginning enrichment to 60 percent in April 2021, a level far closer to weapons grade, and using advanced centrifuges that enrich uranium more efficiently. Although Iran’s decision to accelerate its uranium enrichment program was largely directed at gaining leverage to push the United States back to talks and responding to sabotage, the advances created a swift option to produce weapons-grade uranium (about 90 percent enriched). As a result of these activities, Iran can now produce enough weapons-grade material for 5-6 bombs in about two weeks as of late 2024. This timeframe, known as breakout, was roughly 2-3 months when the JCPOA was negotiated and about 12 months when the nuclear deal was fully implemented – through the final year of the Obama administration until May 2019. Iran would likely still need 6-12 months to build a nuclear weapon, but that work would be done covertly and be more challenging to detect and disrupt.
Given the irreversibility of Iran’s knowledge gains, a new deal could extend breakout by limiting uranium enrichment levels, capping stockpiles that can be readily enriched to higher levels, and reducing the number of operating centrifuges. But it will be impossible to achieve a breakout time similar to the 12 months achieved by the JCPOA. This is because the knowledge Iran has gained will allow it to more quickly reconstitute its nuclear program. As a result, independent monitoring by international watchdogs at the International Atomic Energy Agency (IAEA)– which was a key emphasis of the JCPOA – will be even more important in a new nuclear agreement to ensure rapid detection of any deviation from Iran’s declared program.
Gaps in IAEA Monitoring. Second, gaps in the IAEA’s current monitoring increase the risk that Iran has diverted materials to a covert program and make it more challenging for the agency to provide assurance that Iran’s nuclear program is entirely peaceful. When Iran was fully implementing the JCPOA, its nuclear program was subject to intrusive verification measures that put every aspect of Iran’s nuclear program under strict IAEA monitoring. However, as part of the response to the Israeli assassination of Iranian nuclear scientist Mohsen Fakhrizadeh in November 2020, Iran passed a law requiring the Atomic Energy Organization of Iran to suspend the more intrusive monitoring required by the JCPOA, including implementation of its commitments under the additional protocol to Iran’s safeguards agreement with the IAEA. That agreement (which Iran had been required to implement under the JCPOA) had provided international inspectors with access to sites that support Iran’s nuclear program but do not house nuclear materials. This includes facilities such as centrifuge production workshops and Iran’s uranium mines.
As a result of Iran’s decision to limit access, the IAEA has not inspected key nuclear facilities in Iran since February 2021, increasing the risk that Iran has diverted materials to covert sites. IAEA Director General Rafael Mariano Grossi even admitted in November 2023 that the agency cannot account for all of Iran’s centrifuges. Furthermore, Iran halted the implementation of a provision of its legally binding safeguards agreement, known as modified Code 3.1, that requires it to provide notification to the agency when a decision is made to construct a new nuclear facility. Early access to design plans helps the IAEA develop a more effective safeguards approach. Iran’s failure to provide information about the new sites complicates the IAEA’s ability to provide assurance that Iran’s nuclear program is peaceful and that there has been no diversion to non-peaceful purposes.
Shift in Iran’s Nuclear Doctrine. The third significant factor is the apparent shift in Iran’s nuclear doctrine. Iran has long denied that it pursued nuclear weapons in violation of its Nuclear Nonproliferation Treaty (NPT) commitments, despite ample evidence from the IAEA and the U.S. Intelligence Community that Iran had an organized nuclear weapons program through 2003. Over the past year, however, Iranian policymakers openly discussed the possibility that Tehran would rethink Supreme Leader Ayatollah Ali Khamanei’s fatwa prohibiting nuclear weapons if necessary for the security of the state.
This shift in nuclear doctrine appears designed to leverage Iran’s status on the threshold of nuclear weapons by threatening to weaponize to prevent further attacks. By raising the possibility that the Supreme Leader’s fatwa prohibiting nuclear weapons can be overturned, Iranian officials are socializing the concept of a nuclear deterrent. Furthermore, the threats to develop weapons will put more pressure on the Iranian government to follow through on building a weapon if Iran is attacked.
Trump’s Path to a Deal
Further complicating the challenges posed by Iran’s nuclear advances and shift in doctrine is the short timeframe that Trump will have to reach a deal. His administration faces a deadline in October 2025, when the option to reimpose UN sanctions on Iran expires. The mechanism for restoring those measures, known as snapback, cannot be vetoed. The United States cannot trigger snapback due to Trump’s decision to withdraw from the JCPOA in 2015, but the United Kingdom and France, as participants in the nuclear deal and permanent members of the Security Council, can do so. In a Dec. 6 letter to the Security Council, the United Kingdom and France, along with Germany, reiterated “our determination to use all diplomatic tools to prevent Iran from acquiring a nuclear weapon, including using snap back if necessary.”
If snapback is triggered, negotiations are still possible, but the focus will likely shift to deterring Iran from withdrawing from the NPT, which the Pezeshkian administration has threatened to do if UN sanctions are reimposed.
Furthermore, given how quickly Iran can break out, NPT withdrawal would significantly increase the likelihood of military strikes against Iranian nuclear facilities, even if there is no evidence of weaponization. If Iran withdraws from the NPT, it would no longer be legally obligated to implement safeguards. U.S. and Israeli intelligence may still detect breakout or a move to weaponization, but it will be much more challenging to track Iran’s nuclear materials and activities without the IAEA’s presence, increasing the risk of miscalculation.
To avert a crisis in October and reduce the risk of Iranian withdrawal from the NPT, the Trump administration must be ready to move quickly to engage Iran after taking office. Ahead of Trump’s inauguration, Iran appears focused on maximizing its leverage while publicly reiterating its interest in a deal. The Trump administration might be similarly tempted to ratchet up sanctions pressure upon taking office, but attempting to consolidate pressure before commencing talks would risk wasting the 6-7 months Trump will have to reach a deal. The spectre of UN snapback should create more than enough leverage on the U.S./UK/France side of the negotiating table, along with a massive unilateral U.S. sanctions program currently in place, to strike a balanced interim deal.
The Contours of a Limited Nuclear Deal
The short timeframe for reaching and implementing a deal suggests that the Trump administration should focus on a limited agreement that addresses Iran’s most proliferation-sensitive activities and, most critically, increases IAEA monitoring and access to nuclear facilities. The scope of the deal will need to be carefully calibrated. Too comprehensive of an agreement would be technically challenging to negotiate in the short time frame. If a deal is too limited, however, it may not be sufficient to mitigate the risks of proliferation and conflict over Iran’s nuclear advances.
To thread this needle, the United States should focus on three areas of Iran’s nuclear program:
Intrusive Monitoring. First, the Trump administration should prioritize increased monitoring of Iran’s nuclear facilities, including restoring access to sites that support the program but do not contain nuclear material. The most straightforward option would be for Iran to provisionally implement the additional protocol to its safeguards agreement, which it did as part of the JCPOA from January 2016 to February 2021. The additional protocol would give inspectors access to sites such as Iran’s centrifuge production facilities and more tools to follow up on any evidence of undeclared nuclear activities. If it is not politically feasible for Iran to implement the additional protocol, the deal could include regular technical visits for the IAEA to inspect facilities not covered by Iran’s legally required safeguards agreement. This access is critical for the IAEA to provide assurance that Iran is not diverting materials to a covert program.
In addition to expanding IAEA inspections, a limited deal should include online enrichment monitoring to provide assurance that any move to weapons-grade levels would be quickly discovered and an agreed-upon process and timeframe for Iran to provide the IAEA with information about unmonitored activities that took place after Iran suspended the additional protocol in February 2021. Including the latter provision in a limited deal will help the IAEA begin to recreate baseline inventories for certain materials, such as uranium ore concentrate and centrifuge components. Baselines will be necessary for verifying limits imposed by any new deal. Additionally, reconstructing the history of Iranian activities will provide further clarity about whether key components of Iran’s nuclear program are accounted for.
Enrichment limits. A deal should also seek to extend Iran’s breakout time by limiting Iran’s uranium enrichment program. This should include caps on Iran’s highly-enriched uranium, or HEU (both the 20 and 60 percent stockpiles), stored in gas form. Excess material could be blended down or converted into powder. HEU in powder form poses less of a risk because it must be converted back to gas before being enriched to weapons-grade levels. This option may be more attractive for Iran than blending it down to lower levels, given that it views its HEU as leverage and is unlikely to give it up completely as part of a limited deal.
In addition to stockpile caps, a deal should limit further enrichment to 5 percent and freeze centrifuge production and installation. In a limited initial deal, Iran could keep all of the machines installed as of the November 2024 IAEA report but would commit not to operate any installed machines that are not enriching uranium or deploy new machines.
Weapons-related activity limits. The third area of focus should be a prohibition on certain weaponization-related activities, including the production of uranium metal and certain types of explosive testing. Given Iran’s technical nuclear advances and its ability to quickly produce weapon-grade uranium, even with enrichment limitations in place, blocking Iran’s ability to weaponize is more critical now than it was in the JCPOA. The JCPOA did include a prohibition on certain weaponization activities, but it did not address how to verify Iran’s compliance. It is unlikely Iran and the United States could agree on monitoring mechanisms to ensure the absence of certain weaponization activities in the short timeframe for reaching a limited deal. But even without verification, prohibiting these activities would have benefits, such as preventing Iran from gaining knowledge relevant to the weaponization process. Additionally, if Iran was caught conducting weapons-relevant research, it would cast serious doubt on Iran’s intentions to negotiate and implement a deal in good faith.
The U.S. Side of a Limited Deal. In exchange for these nuclear restrictions, the United States should put meaningful sanctions relief on the table. This could include releasing additional frozen Iranian assets held abroad and transferring them to accounts set up in Qatar to pay for approved humanitarian transactions. The United States could also look at waivers for Iranian oil sales up to an agreed-upon cap.
The Trump administration will also likely look for opportunities for U.S. businesses to benefit from any sanctions relief package. Providing waivers for specific commodities that Iran is interested in, such as civilian airplanes, would provide benefits to both the United States and Iran.
Embed Nuclear Diplomacy in a Regional Security Approach
A limited nuclear deal can reduce the immediacy of Iran’s proliferation risk, but the threat will remain so long as Iran sees deterrence value in its nuclear program and its ability to quickly scale up its program to produce nuclear weapons. But the short time frame for de-escalating nuclear tensions makes it challenging to pursue a transformative agreement with Iran, address broader regional security challenges, or even a comprehensive nuclear deal. Trump, however, could increase the sustainability of a deal and lay the groundwork for a more comprehensive accord by embedding nuclear negotiations within a broader strategy of support for de-escalating regional tensions.
In the short term, the Trump administration should condemn loose talk of strikes against Iran’s nuclear program and send a strong signal to Israel that the United States will not support preventive military strikes, which would be both unlawful and counterproductive to U.S. or Israeli long-term strategic interests.
More broadly, the Trump administration’s strategy for the Middle East should take into account that Iran’s security concerns drive its interest in nuclear weapons. Supporting efforts between Saudi Arabia and Iran to strengthen ties and an end to Israel’s war in Gaza, for instance, would also be useful in de-escalating regional tensions and creating an environment more conducive to negotiating a more comprehensive agreement that builds on a limited nuclear accord.
Trump faces a significant challenge in addressing Iran’s nuclear program, but he also has an immediate opportunity to reduce its proliferation risks. His administration must be prepared to move quickly to engage Iran on a limited agreement that rolls back Iran’s most proliferation-sensitive activities and increases monitoring. By reaching a deal that reduces the urgency of the proliferation threat, the next Trump administration can create space for negotiations on a longer, more comprehensive agreement that blocks Iran’s pathways to nuclear weapons.
– Kelsey Davenport (LinkedIn – X) is the Director for Nonproliferation Policy at the Arms Control Association, where she focuses on the nuclear and missile programs in Iran, North Korea, India, and Pakistan and on international efforts to prevent proliferation and nuclear terrorism. Published courtesy of Just Security.
