Vice President JD Vance on Thursday, 18 June declared that a 60-day countdown has formally begun to determine whether a newly signed US-Iran memorandum of understanding can be converted into a durable nuclear agreement — or whether it will collapse under the weight of decades of mutual distrust. Speaking at a White House press briefing, Vance offered the most detailed public account yet of how the Trump administration intends to move from a framework accord to a final settlement.

Technical Negotiations Move to Switzerland

The administration is shifting gears from broad political discussions to highly technical talks involving nuclear experts, diplomats and security officials. Vance said these negotiations are expected to begin in Switzerland as early as this weekend, focusing on implementation specifics rather than overarching political principles.

Key issues on the table include the disposal of highly enriched uranium stockpiles, verification mechanisms, inspection procedures and compliance benchmarks. 'How do you destroy this highly enriched uranium, all that stuff that you really just have to get into the nitty gritty on,' Vance said. He added that he personally plans to lead the US negotiating team, subject to coordination with Iranian officials.

Verification Over Trust

A dominant theme at the briefing was the administration's insistence that verified conduct — not written commitments — will determine whether Iran receives any economic relief. 'We don't trust words. We trust action, and we trust conduct,' Vance said.

According to Vance, Iran has committed to allowing inspections, eliminating highly enriched uranium stockpiles and accepting monitoring mechanisms designed to prevent the re-emergence of a nuclear weapons programme. 'They have promised not to enrich,' he said, while stressing that sanctions relief will follow only after measurable compliance. 'Words don't matter… we're about verification,' he added.

The administration's stated objective extends beyond halting current nuclear activities — it aims to ensure Iran cannot rebuild weapons-grade capacity 'many, many years from now.'

Congress Briefings and Legal Questions

Vance disclosed that lawmakers would shortly receive formal briefings on the memorandum, amid growing scrutiny from both Republican and Democratic legislators. He also defended the administration's authority to temporarily ease certain sanctions without congressional approval, saying, 'We feel quite confident that we can temporarily lift those sanctions without going to Congress.'

The legal question carries weight: any agreement that reshapes US policy toward Iran and the broader Middle East could require legislative ratification, and opposition lawmakers have already signalled they intend to assert oversight.

Economic Leverage and Frozen Assets

Vance firmly rejected suggestions that Tehran was receiving economic rewards ahead of demonstrated compliance. 'They don't get anything unless they change their behavior,' he said, adding that the United States retains substantial leverage through sanctions and frozen Iranian assets held abroad.

'We're not releasing a single dollar of that money until the Iranians perform,' he said, directly disputing reports claiming billions had already been freed. He described any future sanctions relief as incremental and reversible: 'As they dial up their good behavior, we can dial up the economic relief. If they dial down their good behavior, we can turn it off.'

Strait of Hormuz and Military Posture

Vance indicated that the broader negotiations will also address long-term security arrangements in the Strait of Hormuz, a critical global energy corridor. The memorandum reportedly envisions discussions among Iran, Oman and Gulf Arab states to establish a framework preventing future disruptions to international shipping. 'We don't ever want this to happen again,' he said, stressing that the US opposes any tolls on commercial traffic through international waterways.

On military posture, Vance said troop reductions would occur only after full Iranian compliance, and would apply to forces deployed during the crisis rather than longstanding US military positions across the Gulf. 'If they don't perform, every sanction will come back on,' he said. 'We've still got all the cards.'

The coming weeks will be closely watched across Europe, the Middle East and Asia, where governments have a direct stake in regional stability and the uninterrupted flow of oil through the Gulf. Whether the 60-day window produces a verifiable deal or a fresh breakdown will shape the geopolitical landscape well beyond Washington and Tehran.