US-Iran Nuclear Talks Collapse in Islamabad After 21-Hour Marathon

The highest-level direct negotiations between Washington and Tehran since the 1979 Islamic Revolution ended in acrimony and stalemate early Sunday, after a 21-hour marathon in Islamabad failed to produce an agreement. US Vice President J.D. Vance, visibly grim, announced that Iran had "chosen not to accept our terms" before boarding Air Force Two for the return journey. The collapse of the Pakistan-brokered talks leaves the fragile two-week ceasefire hanging by a thread and the strategically vital Strait of Hormuz still choked by mines and Iranian restrictions.

Viewed from Washington, the core obstacle was unambiguous: Iran declined to offer what Vance called an "affirmative commitment" to forgo nuclear weapons not just in the short term but indefinitely, along with the means to rapidly produce them. American negotiators characterised their position as a final offer, insisting on irreversible, verifiable guarantees. Tehran, however, painted a different picture, accusing the United States of "unreasonable demands" and linking any reopening of Hormuz to a "reasonable agreement" that would unfreeze billions in Iranian assets held abroad. The three-way tensions over the strait, uranium enrichment, and sanctions relief proved insurmountable.

The meeting itself was an extraordinary diplomatic gambit, convened after President Donald Trump threatened to obliterate Iranian civilisation and then abruptly announced a truce with a deadline for Hormuz’s full reopening. The Iranian delegation was led by parliamentary speaker Mohammad Bagher Ghalibaf, while Vance was joined by envoy Steve Witkoff and Jared Kushner. Pakistan’s military chief acted as mediator. Even as the talks progressed, two US destroyers transited Hormuz to begin mine-clearing operations — a signal of American resolve that Tehran denounced as provocative.

European and Indo-Pacific capitals reacted with a mixture of dismay and urgency. Australian Foreign Minister Penny Wong called the outcome "disappointing" and urged an immediate return to the table, warning that any escalation would impose a severe human and economic cost. Analysts in London note that the ceasefire was already fracturing before the talks began, as Israel conducted massive strikes on Lebanon that killed hundreds, casting doubt on whether the truce genuinely applied across the region. Iran’s proxies and its ability to choke global energy flows give it significant leverage, and some observers argue that Israeli Prime Minister Benjamin Netanyahu has a long history of spoiling US-Iran diplomatic openings.

What comes next is dangerously uncertain. The US has framed the failure as Iran’s loss, but Tehran’s state-linked media insisted "diplomacy never ends" and that contacts will continue. A second round of talks had been tentatively planned, yet the mutual accusations of bad faith — and the ongoing military manoeuvres — will make a swift resumption difficult. The war that began on 28 February has now entered a diplomatic phase without diplomacy’s chief reward: a durable pause. For now, the door remains only a crack ajar, as both sides weigh the cost of walking away entirely.