The United States Senate voted to advance a war powers resolution aimed at compelling President Donald Trump to withdraw American military forces engaged in hostilities against Iran. The procedural motion passed by a narrow 50 to 47 margin, marking the first time such an effort has successfully moved out of the Senate Foreign Relations Committee after multiple previous attempts.

The breakthrough came after Senator Bill Cassidy broke with his party’s leadership following his recent primary election loss, joining Senators Rand Paul, Susan Collins, and Lisa Murkowski in supporting the measure. The resolution, sponsored by Senator Tim Kaine, now heads to the Senate floor for formal consideration. One Democrat, Senator John Fetterman, voted against advancing it.

Despite the symbolic victory for opponents of the military action, the resolution faces steep obstacles. Even if approved by the full Senate, it would still require passage in the House of Representatives and the president’s signature before it could take effect.