The US Senate has voted 50-48 to adopt a War Powers Resolution directing President Donald Trump to end hostilities against Iran unless Congress authorises further military action.
The measure was approved under Section 5(c) of the 1973 War Powers Resolution after it had passed the House.
Republican Senators Bill Cassidy of Louisiana, Susan Collins of Maine, Lisa Murkowski of Alaska and Rand Paul of Kentucky joined Democrats in supporting the resolution.
Democratic Senator John Fetterman of Pennsylvania voted against it, while Republican Senators Mitch McConnell of Kentucky and Dave McCormick of Pennsylvania did not vote.
Bipartisan pushback
The practical impact of the measure remains uncertain as Washington and Tehran have already reached an interim peace agreement.
However, the non-binding resolution represents the strongest symbolic pushback from Capitol Hill against the war to date after nine previous votes failed to secure a simple majority needed to pass in the Senate.
The vote follows weeks of conflict that disrupted global energy markets and pushed US fuel prices sharply higher.
The Senate vote came less than a week after the Trump administration announced an interim understanding with Iran aimed at halting hostilities while negotiations toward a broader settlement continue.
On 17 June, Trump and Iranian President Masoud Pezeshkian signed a memorandum of understanding electronically to achieve a lasting peace agreement.
The two sides are now engaged in technical negotiations during a 60-day ceasefire, seeking to resolve disputes over Iran's nuclear programme and restore commercial shipping through the Strait of Hormuz to pre-conflict levels.
