The U.S. Senate passed legislation on Thursday to limit President Donald Trump’s ability to wage war against Iran, rebuking him weeks after a strike against an Iranian military commander and Tehran’s retaliation raised fears of broader regional conflict.

Eight of Trump’s fellow Republicans joined Democrats to pass the war powers resolution by 55-45. The measure would require Trump to remove U.S. troops engaged in hostilities against Iran unless Congress declares war or passes a specific authorization for the use of military force.

Trump has promised a veto, and there is not expected to be enough support to muster the two-thirds Senate super majority to override. Fifty-three of the 100 senators are Republicans, who rarely break with the president.