Trump has notified Congress that the U.S. is embarking on a new phase of war against Iran, using the War Powers Resolution framework. The notice sets off renewed debate over whether congressional authorization is required for continued or expanded military action. Lawmakers have been sharply divided, with some arguing the administration has not met legal thresholds, while others say the president’s authority as commander in chief is sufficient. Negotiations with Iran are also cited as context for the political fallout on Capitol Hill.