Trump Signals Openness to Time-Limited Iran Nuclear Moratorium, Dropping Permanent-Ban Stance

President Donald Trump told reporters aboard Air Force One on May 16 that a 20-year moratorium on Iran's nuclear program would be sufficient for a deal, a public break from his administration's longstanding position that Iran must permanently and irreversibly dismantle all enrichment capacity. The shift allows for Iran to enrich uranium at some future point, even decades out, a departure from the administration's repeated public insistence that it would accept nothing less than a full, permanent surrender of Iran's nuclear ambitions. Trump's acknowledgment came aboard Air Force One following his return from a two-day summit in China, and it appears to represent a recalibration of a position he had maintained consistently across months of negotiation.

The remarks landed against the backdrop of a war now in its third month. The conflict began on Feb. 28 when the United States and Israel launched coordinated strikes that killed Supreme Leader Ali Khamenei and struck Iran's military and nuclear infrastructure. The United States and Iran agreed to a two-week ceasefire on April 8, mediated by Pakistan. Post-ceasefire negotiations have been conducted through Pakistani intermediaries, with Special Envoy Steve Witkoff and senior presidential adviser Jared Kushner serving as the principal U.S. negotiators. The current memorandum of understanding under discussion is being crafted by Witkoff and Kushner together with several Iranian officials. Secretary of State Marco Rubio has described the process as "highly complex and highly technical." [POLITICO]

The gap between the two sides on the duration of a moratorium has been a central sticking point throughout the post-ceasefire talks. The duration of a moratorium on uranium enrichment has been actively negotiated, with U.S. officials initially demanding 20 years while Iran proposed a five-year moratorium. The United States has sought a moratorium of at least 12 years, with a provision that would extend the moratorium if Iran were found to have violated it. Earlier this week, Trump declared Iran's most recent counter-proposal "totally unacceptable," with Iranian state media simultaneously reporting that Tehran had rejected what it described as Washington's "excessive demands," with the core dispute centering on Iran's enriched uranium stockpile, enrichment infrastructure, and sovereignty over the Strait of Hormuz.

On the uranium stockpile itself, the administration's demand remains unresolved. Key U.S. demands during recent talks have included Iran surrendering its existing stockpile of roughly 440 kilograms of highly enriched uranium and fully dismantling enrichment facilities struck by U.S. forces in June 2025 at Natanz, Isfahan, and Fordow. Trump told reporters that Iran had stated it cannot remove the stockpile because it lacks the technology, and that only China and the United States have the equipment to extract what he describes as "nuclear dust" from the obliterated nuclear facilities. He said Iran had previously agreed to have the stockpile removed but then reversed course. The buried highly enriched uranium is believed to be enriched to 60 percent. Weapons-grade enrichment requires reaching 90 percent.

Trump's 20-year figure carries notable legal and historical resonance. The stated term mirrors the much-criticized sunset clause in the 2015 Joint Comprehensive Plan of Action, which would have allowed Iran to enrich unlimited quantities of uranium after expiration. Trump withdrew the United States from that agreement in 2018, citing the sunset clause as unacceptable and warning it would spark a regional nuclear arms race. Any formal agreement on Iran's nuclear program would trigger statutory congressional review. If talks lead to a formal agreement on Iran's nuclear program, the administration would be required to submit the accord for congressional review under the Iran Nuclear Agreement Review Act. The JCPOA's remaining multilateral provisions formally expired in October 2025, removing that legal architecture from the table. The United States unilaterally withdrew in 2018, and many of the JCPOA's provisions expired in October 2025.

The legal context for continued U.S. military posture rests on executive authority. Congress has not explicitly authorized the use of military force against Iran. In February 2025, Trump signed National Security Presidential Memorandum 2, which directed U.S. officials to impose "maximum pressure" on Iran to compel it to abandon its nuclear program and support for terrorist groups. The proposed memorandum of understanding being negotiated would, if agreed upon, declare an end to the war and start a 30-day period of negotiations on a detailed agreement to open the Strait of Hormuz, limit Iran's nuclear program, and lift U.S. sanctions. If negotiations collapse, U.S. forces would be able to restore the blockade or resume military action.

The durability of any time-limited arrangement faces substantial technical challenges independent of the political ones. In the years following the collapse of the JCPOA, Iran acquired significant technical knowledge in centrifuge production and operation that cannot be destroyed by military strikes. By June 2025, Iran's best centrifuges were roughly six times as efficient as those in existence in 2015. By 2025, Iran demonstrated an ability to install centrifuge cascades nearly three times faster than in 2015, compressing the time Tehran would need to produce weapons-grade material even if forced to rebuild its nuclear infrastructure from scratch. Those verification and reconstitution risks form the core of what U.S. negotiators, IAEA officials, and nonproliferation analysts have identified as the primary weakness in any finite-term arrangement, and they now fall squarely within the scope of the 30-day detailed negotiation that the proposed MOU is designed to initiate.