Volume 18, Issue 4, June 22, 2026
The June 2026 Islamabad memorandum of understanding to halt the U.S.-Israeli war against Iran and reopen the Strait of Hormuz is a flawed but welcome development. This interim agreement aims to halt a misbegotten conflict that has killed thousands of people, disrupted the global economy, and failed to address the proliferation risk posed by Iran’s nuclear program, which cannot be bombed away.
The MOU itself does not block Iran’s pathways to nuclear weapons, but by ending the fighting and committing both sides to further diplomacy, it could create a pathway for resuming negotiations to verifiably curb Iran's nuclear program—negotiations that were underway when the United States and Israel launched their illegal attack on Iran on February 28.
Reaching an effective nuclear nonproliferation agreement in the 60-day timeframe established by an MOU will not be easy. But members of the U.S. Congress and governments in the Middle East should support this opportunity to negotiate an effective, verifiable, and durable nuclear nonproliferation deal with Iran and refrain from actions and threats that could derail the negotiating process.
If a nuclear agreement is reached, it should be judged on the merits. Namely, do the nuclear restrictions significantly increase the time it would take to build a bomb if Tehran made the decision to do so? Does the deal put in place an effective verification regime to monitor Iran’s compliance with the negotiated limits and quickly detect any deviations or illicit activity so that the international community has time to respond to a move toward weaponization?
There is, and will be, an understandable tendency to compare the MOU and any future agreement that U.S. President Donald Trump negotiates with the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), between Iran and the P5+1 (China, France, Germany, Russia, the United Kingdom, and the United States).
Contrary to Trump's misrepresentations, the JCPOA proved to be an effective, verifiable nonproliferation agreement; many of its provisions could inform negotiations today. But there is limited utility in direct comparisons between any deal negotiated by Trump and what the JCPOA achieved.
What was technically possible and necessary for an effective deal in 2015 is not what is possible and necessary for a good deal in 2026. Iran’s nuclear program and its pathways to the bomb are fundamentally different now than when the JCPOA negotiations commenced, and a new deal must address those shifts.
The JCPOA should, however, serve as a reminder of what is possible when the United States pursues constructive diplomatic solutions. Similarly, Trump’s decision to withdraw from the JCPOA in 2018, despite Iran’s compliance, should be a warning against abandoning effective diplomatic agreements without a viable “Plan B.” Trump’s disastrous 2026 war with Iran, and subsequent efforts to return to nuclear talks, is a tacit admission that "maximum pressure" and military action cannot destroy Iran's nuclear weapons capacity or pressure its government to abandon what it perceives as its nuclear rights under the nuclear Nonproliferation Treaty (NPT).
Although Trump mismanaged two previous attempts to negotiate with Iran since resuming office in 2025, there is still a chance that this MOU leads to an effective agreement. The failure to credibly test this diplomatic opportunity increases the risk that talks will collapse and war resumes.
A Chance to Resume Critical Talks
Iran's nuclear program continues to pose a serious nonproliferation risk, but it is not an imminent threat.
The U.S. and Israeli decision to illegally strike key nuclear targets in Iran in June 2025 set back the country’s nuclear program and halted proliferation-sensitive nuclear activities, such as uranium enrichment to near weapons-grade levels. Nevertheless, key materials and technologies that would be needed if Iran made the decision to build a bomb survived the strikes. The subsequent U.S. and Israeli attacks on Iran in 2026 did not fundamentally alter the status of Iran's nuclear program, making clear that airstrikes cannot eliminate Tehran’s capability to build a bomb.
The continued risk posed by Iran’s remaining nuclear infrastructure and weapons-relevant institutional knowledge underscores the importance of testing this diplomatic opportunity to reduce Iran’s proliferation risk in the long term.
The MOU is, fundamentally, a non-nuclear deal that leaves key nuclear issues unresolved. It sets a 60-day timeline, extendable by mutual consent, for negotiating limits on Iran’s sensitive nuclear activities as part of a broader agreement.
In the text of the MOU agreement:
- Iran reaffirms that it will never seek to build or acquire nuclear weapons. This clause is a useful reiteration of Iran’s commitment not to weaponize, given that the U.S.-Israeli attacks have prompted some Iranian policymakers to call for withdrawal from the NPT and spurred more intensive Iranian? debate on the value of a nuclear deterrent. But this pledge is neither new, nor sufficient. Iran has said multiple times that it will not seek or develop nuclear weapons. Most notably, as an NPT member state, it is legally obligated not to do so. This NPT obligation did not stop Iran, however, from illicitly pursuing nuclear weapons prior until 2003 and will not be an adequate barrier in the future.
- The United States and Iran agreed to resolve the disposition of stockpiled, enriched material [by, at a minimum] down-blending on site under the supervision of the IAEA. This is an important and positive step that would increase the amount of time it would take to produce enough fissile material for a bomb. Involving the International Atomic Energy Agency is a necessary step for verifying compliance and ensuring that nuclear materials are accounted for. But there are still questions about the process and timeframe for disposition that must be worked out, as well as the storage location for the down-blended material.
- The two parties also agreed to discuss the issue of enrichment and other mutually agreed matters related to … Iran’s nuclear needs, based on the statutory framework being agreed upon in the final deal. The details on duration and scope of any limits, and how such commitments are verified, will be critical in determining how far these measures set back Iran’s nuclear program, as well as when, and under what conditions, Iran could rebuild its fuel cycle in the future. The JCPOA limitations pushed Iran’s breakout time -- the time it would take to produce enough fissile material for a bomb -- to 12 months for more than a decade. Because of Iran’s knowledge gains since then, achieving a 12-month breakout in a new deal may not be feasible. It is also not necessary. A multi-month breakout, combined with intrusive inspections to detect it, would provide time for the international community to respond.
- Although not reflected in the MOU, U.S. officials say that Iran and the IAEA worked out an agreement on resuming inspections, which is a necessary step after Iran suspended access to bombed nuclear sites following the 12-day war in June 2026. But again, there are a few details on the timing, scope, or frequency of inspections, all of which have a bearing on the effectiveness of the inspections.
Addressing these issues, plus other measures such as additional verification, which are necessary for an effective, durable agreement, will be challenging to negotiate in 60 days. Although that timeframe is extendable, drawing out the talks could risk that Trump loses interest in the negotiations or allows spoilers to disrupt the diplomatic process. Israeli Prime Minister Benjamin Netanyahu, for instance, has already issued maximalist nuclear terms and made clear that Israel is not bound by the MOU.
In a June 22 statement, issued after the first round of negotiations on a final agreement began, mediators Pakistan and Qatar announced, “the creation of a mechanism for further technical talks” and the establishment of working groups, including one on nuclear issues. This suggests a more effective process compared to Trump’s earlier diplomatic approaches.
Given the subpar performance of the lead U.S. negotiators in past talks, the U.S. team should be supported by bonafide nonproliferation experts in the U.S. government. When appropriate, both sides should consult with IAEA technical experts to ensure that verification measures are feasible and address what is necessary for the agency to fulfill its mandate.
The Contours of an Effective Nuclear Agreement
There is no single pathway to an effective deal. Different combinations of limits and monitoring could produce an agreement that gets the job done. Key issues could be effectively addressed in the following ways:
Highly enriched uranium stockpile: To verifiably neutralize the proliferation risk posed by Iran’s stockpile of highly enriched uranium (HEU), particularly the 440 kilograms of uranium enriched to 60 percent uranium-235, which is near-weapons grade and likely intact but not immediately accessible, the parties should agree to:
- Excavate the HEU under IAEA supervision and then downblend the material within Iran to less than five percent U-235, a level suitable for power reactors and significantly below the 90 percent considered weapons grade. The United States, or a third party, could agree to provide any necessary equipment or funding to safely complete that process.
- Iran could then, under IAEA supervision, ship the down-blended uranium to the international fuel bank in Kazakhstan, where it would remain the property of Iran and could be returned if necessary for future reactor fuel production. Other alternatives could be for Iran to transfer the material to Russia or sell it. It may be possible for Iran to retain the down-blended uranium, but the risks posed by keeping the material in Iran would depend in part on the level of IAEA supervision and the other limits in an accord.
Iran's uranium enrichment capabilities: Iran’s two operational uranium enrichment facilities, Natanz and Fordow, were damaged significantly in June 2025 and do not appear to be operational. Tehran notified the IAEA of a third enrichment facility at Esfahan in June 2025, but the agency did not have a chance to inspect the facility before Israel attacked Iran on June 13. Iran has told the IAEA that the facility was damaged, but inspectors have not had access to the site to verify those claims.
Although there is uncertainty about the Esfahan facility, it appears unlikely that Iran has an operational industrial-scale enrichment facility. Nor does it have a practical need for enriched uranium to meet its current fuel needs. The Bushehr light-water nuclear power plant is fueled by Russia, and Iran has a multi-year supply of fuel on hand for the Tehran research reactor.
Iran does still have the know-how to enrich and likely a stockpile of centrifuges that survived the war. But even if Iran were starting from zero, it could revive its centrifuge production and uranium enrichment relatively quickly and return to the threshold of nuclear weapons in less than a year.
Trump appears to have moved away from his earlier demand that Iran should permanently suspend enrichment, but will likely be pressured, including by Netanyahu, to resume demands for zero enrichment. Insisting that Iran permanently forego enrichment is not necessary for an effective agreement and would only drive Iran from the negotiating table.
Uncertainties about Iran’s stockpile of materials and its rapid build-back potential suggest that suspending uranium enrichment for a multi-year period is an important aspect of a nuclear deal, but insufficient. A meaningful agreement should consider limits on the broader scope of activities that enable uranium enrichment.
The two sides should agree to detailed, verifiable terms that could include the following:
- A multi-year suspension of uranium enrichment, uranium milling and conversion, and centrifuge research, development, and production. The duration will need to be negotiated and likely fall between the 20 years the Trump Administration reportedly wants, and the five years that Iran has suggested.
- Any resumption of enrichment should be contingent on Iran demonstrating a practical need. A deal could, for instance, could allow domestic uranium enrichment and fuel production for nuclear energy purposes and commence only when Iran reaches certain milestones in reactor construction. Furthermore, Iran should agree to cap enrichment to reactor-grade (less than five percent) levels and limit uranium stored in gas form (UF6). A deal could also require Iran to ratify the additional protocol to its safeguards agreement before resuming enrichment.
- Iran and the United States could also agree to actively study and incentivize other nuclear fuel cycle options that reduce proliferation risk, including a bilateral, regional or multilateral approach to uranium enrichment and reactor fuel production. This could have the added benefit of addressing other long-term proliferation risks in the region.
A verifiable suspension on enrichment, combined with the dilution of the HEU stockpile, and limits on remaining low-enriched uranium stockpiles, would provide much greater assurance that Tehran could not quickly dash for a bomb if the decision were made to do so.
Although Iran is less likely to take the plutonium route to nuclear weapons, this issue should also be addressed in a final deal. Iran could agree to forgo plutonium reprocessing, and a deal could provide an incentive for Tehran to ship its spent nuclear fuel (which contains plutonium) from Bushehr reactor back to Russia, which is obligated to take it back under a previous agreement.
Resuming IAEA Inspections. An essential element of any effective new agreement must be the swift resumption of IAEA inspections and an intrusive, agency-led monitoring regime to verify compliance.
Trump administration officials have said little about the U.S. demands on monitoring and verification, but it should be a primary focus in negotiations.
Getting the monitoring provisions right is critical because Iran has blocked inspectors from accessing nuclear sites struck in June 2025, and the extent of the damage and whereabouts of Iran’s nuclear materials remain unknown. The agency has lost its continuity of knowledge over Iran’s nuclear materials and key technologies, such as centrifuges.
The IAEA will face serious challenges trying to restore baseline inventories, and it may be unclear for some time what, if any, materials were destroyed during the war or diverted to covert sites. Robust monitoring and verification will be even more critical to the success of a future deal, given that uncertainties and gaps in the agency’s accountancy may persist and that Iran’s irreversible knowledge gains since breaching the JCPOA would allow it to reconstitute its uranium enrichment capacity more quickly.
According to a June 18 Associated Press report, Trump’s envoy, Steve Witkoff, told U.S. lawmakers in a closed briefing that Iran will invite the IAEA to inspect its nuclear sites and begin work on accounting for its enriched material stockpiles. Iran is already obligated to do this as part of its NPT-required comprehensive safeguards agreement with the agency. Resuming safeguards-required inspections would be a positive step that could inform negotiations, but it is insufficient.
As part of any new nuclear deal:
- Iran should agree to the return of IAEA inspectors to all nuclear sites in Iran without unwarranted restrictions as soon as possible. A deal should also explicitly state that Iran’s safeguards implementation includes adherence to Modified Code 3.1, a provision in IAEA comprehensive safeguards agreements requiring states to submit preliminary design information for new nuclear facilities to the IAEA as soon as the decision to construct has been made. In February 2021, Iran said it unilaterally suspended Modified Code 3.1, which the agency argues is not permissible.
- An agreement could also include time-bound provisions for Iran to provide the agency with updated reports on its facilities and materials. Similar timeframes could be put in place for Iran to respond to IAEA requests for access to undeclared sites and queries for information necessary to fulfill the agency’s mandate. This will prevent Tehran from stonewalling the agency, as it has in the past.
- Iran should agree to adhere to more intrusive safeguards under the terms of the IAEA additional protocol, which provides the agency with access to additional sites and information, and require ratification of that agreement as a condition of future enrichment.
- Additional measures may be necessary depending on other provisions in the agreement, such as continuous surveillance of any remaining enriched uranium stored in Iran.
This combination of measures will provide greater assurance that Iran is implementing its nuclear obligations under any new agreement and not engaging in covert nuclear weapons-related activities. Robust monitoring also benefits Iran by countering misinformation about its nuclear program and activities.
UN Security Council Review and Endorsement
Iran's nuclear program is a global peace and security concern, not just a bilateral issue between Washington and Tehran. As the MOU stipulates, any new U.S.-Iran agreement addressing Iran's nuclear program and sanctions relief should be put before the UN Security Council to ensure its terms are recognized by the international community and enable the Council to help reinforce the full implementation by all parties.
Because China, France, Russia, or the UK could veto a resolution endorsing a deal, the United States and Iran should consult, when necessary, with these states to ensure their nonproliferation concerns are addressed by a final agreement. Security Council action would not just benefit the Iran deal but also help reinforce nuclear nonproliferation norms writ large.
A Better Path: Serious Nonproliferation Negotiations
The 2026 U.S.-Israeli war on Iran proved to be a disaster that failed to advance U.S. strategic goals, including nonproliferation objectives, and inflicted widespread humanitarian consequences in Iran, the region, and beyond.
The war has imposed economic hardships on ordinary Americans and damaged U.S. credibility worldwide. Effectively ending this irresponsible war benefits everyone, especially those in the Gulf region, and opens the way to a negotiated, verifiable agreement to address the most serious security threat posed by Iran: its potential to acquire nuclear weapons.
If the U.S. and Iran can reach a new nuclear deal in the coming weeks or months, it should be measured against what is necessary and technically feasible to verifiably block Iran's pathways to nuclear weapons and detect any prohibited nuclear activities. It should also be measured against the likely alternative—a return to maximum pressure, and possibly war, neither of which will adequately address Iran’s nuclear proliferation risk.
—Kelsey Davenport, Director for Nonproliferation Policy, and Daryl G. Kimball, Executive Director