This resolution tells the President to pull U.S. military forces out of any active combat with Iran unless Congress has formally voted to declare war or specifically authorized that fighting. It's built on a law called the War Powers Resolution, which gives Congress a way to force the President to stop military action it hasn't approved. The measure does still allow U.S. forces to defend themselves, their bases, or allied countries if they're facing an imminent attack, so it's not requiring troops to stand down if they're actually under threat. In short, it's Congress asserting that any broader military conflict with Iran needs its sign-off, not just the President's decision.