This resolution would require the President to pull U.S. military forces out of any combat involving Iran unless Congress has specifically voted to declare war or authorize that military action. In other words, it says the President can't keep troops fighting in or against Iran on his own authority alone — Congress has to sign off first. There's an exception: U.S. forces could still act in self-defense if America or its troops and bases elsewhere in the world are attacked. This mainly affects the balance of power between the President and Congress over decisions to go to war, rather than changing anything else about U.S. relations with Iran.