This resolution tells the President to pull U.S. military forces out of any fighting in or against Iran unless Congress has specifically voted to declare war or authorize that military action. In other words, if U.S. troops are engaged in combat with Iran without Congress's formal sign-off, this would require ending that involvement. It does include an exception: it wouldn't stop the U.S. military from defending itself if American forces, personnel, or facilities anywhere in the world came under attack. Essentially, this is about which branch of government—Congress or the President—gets to decide whether the U.S. goes to war with Iran.