Since 2001, the president has had broad authority to authorize surveillance, detention and airstrikes against certain U.S. adversaries. But that could soon change.
The House Appropriations Committee passed an amendment requiring Congress to vote on repealing the 2001 Authorization for Use of Military Force.
The AUMF lets the president use force against people or organizations involved in the 9/11 terror attacks to "prevent any future acts of international terrorism" against the U.S.
The law initially passed in the Senate 98-0. But some are now concerned the AUMF is too broad. Its definition has been stretched to justify military action more than 30 times in 14 different countries without congressional approval.
Former President Barack Obama cited the AUMF after ordering strikes against ISIS, arguing that since the group split from Al-Qaeda, it was fair game.
Then, President Trump used it to justify the recent strike against a Syrian air base, even though Syria's government wasn't involved in 9/11.
Though Republicans and Democrats don't often agree on how to use the military, there could be bipartisan support in restoring Congress' power to authorize war. Republican Sen. Jeff Flake and Democratic Sen. Tim Kaine partnered up to request a Senate vote on a new AUMF against ISIS, Al-Qaeda and the Taliban.
AUMF opponents like Democratic Rep. Barbara Lee say it gives the president a "blank check to wage war anywhere, anytime, for any length."
But those who want to keep the AUMF say pulling it would tie the military's hands to attack and defeat terrorists. The amendment would repeal the AUMF within 240 days unless Congress votes to keep it around.