This resolution would order the President to pull U.S. military forces back from any combat activity against Iran, unless Congress has specifically voted to declare war or approve that military action. It relies on a law called the War Powers Resolution, which gives Congress a way to force a withdrawal of troops from a conflict the President started without Congress's sign-off. The one exception: U.S. forces could still act if needed to defend themselves or the country from an attack that's about to happen. In plain terms, this is Congress trying to reassert its constitutional say over whether the country goes to war with Iran, rather than leaving that decision solely to the President.