The US Senate has passed a war powers resolution demanding a halt to American military action against Iran, in a 50-48 vote that marks the first time both chambers of Congress have approved such a measure since the War Powers Resolution was enacted in 1973. The outcome represents a significant, if largely symbolic, rebuke of the Trump administration, which launched strikes on Iran alongside Israel on 28 February without seeking congressional authorisation.

Four Republican senators — Lisa Murkowski of Alaska, Susan Collins of Maine, Rand Paul of Kentucky and Bill Cassidy of Louisiana — crossed party lines to vote with Democrats in favour of the resolution. Democratic Senator John Fetterman of Pennsylvania was the only member of his party to vote against it. The narrow result was also shaped by the absence of two Republican senators: Mitch McConnell, who was recently hospitalised for an undisclosed matter, and Dave McCormick of Pennsylvania. The House of Representatives passed its own version of the resolution earlier this month, with four Republicans joining all Democrats in a 215-208 vote.

President Trump reacted sharply, writing on his Truth Social platform that the vote was "poorly timed and meaningless" and accusing senators of making his job harder. "I will get it done, one way or the other, because I always get it done!" he wrote. A White House official argued the measure was moot, pointing to a ceasefire agreed on 7 April and claiming there were no active hostilities from which to withdraw US forces. Analysts noted the limits of the resolution: because it is a concurrent resolution rather than legislation requiring the president's signature, it does not carry full legal force. Middle East analyst Laura Blumenfeld described it as "more of a slap on the wrist than a handcuff."

Nevertheless, the vote adds to mounting pressure on the administration at a delicate diplomatic moment. Last week, Trump signed a Memorandum of Understanding with Iran, starting a 60-day clock for the two sides to negotiate a broader agreement over Tehran's nuclear programme. A first round of peace talks concluded in Switzerland on 22 June. Iran has signalled it intends to maintain administrative control over the Strait of Hormuz — the narrow waterway through which a significant share of the world's oil passes — a position firmly rejected by Secretary of State Marco Rubio. Meanwhile, the Pentagon has asked Congress for roughly $80 billion, mostly to cover the cost of the Iran war, as fuel prices at home remain elevated and public support for the conflict has eroded.

The vote is the tenth time Senate Democrats have forced a war powers vote since the conflict began, and reflects growing unease within the Republican Party itself. Several GOP senators have publicly criticised the terms of the Iran deal, particularly a proposed $300 billion reconstruction fund for Iran — a figure far exceeding the $1.7 billion refunded to Tehran under the 2015 nuclear agreement negotiated by the Obama administration. The tension comes ahead of November's midterm elections, which will determine whether Republicans can hold their slim majorities in both chambers of Congress.