The US Senate Iran resolution passed 50-48 on Tuesday, directing President Donald Trump to remove US forces from hostilities with Iran amid peace talks with Tehran.
The concurrent resolution had already passed the House of Representatives earlier this month. The vote showed rising concern in Congress over the conflict, which began on February 28.
Four Republicans joined nearly all Democrats in backing the measure. One Democrat opposed it, while two Republicans did not vote.
The resolution relies on the 1973 War Powers Act, which limits a president’s ability to keep US forces in hostilities without congressional approval.
However, the measure will not go to the White House for Trump’s signature. That makes the vote largely symbolic unless courts later uphold its force.
The White House has argued that the legislation is unconstitutional and not binding on the president.
Scott Anderson, a senior fellow at the Brookings Institution and senior editor at Lawfare, said the executive branch will likely ignore the measure on constitutional grounds. He said it remains unclear who would have standing to sue for enforcement.