A post-Vietnam law puts a 60-day clock on the use of military force without congressional authorization. The war in Iran – for which the Trump administration sought no approval – hits that 60-day mark May 1, according to the text of the law, the War Powers Resolution, but it’s not at all clear what will happen next.

The Senate rejected Democrats' sixth attempt to limit President Trump's authority to wage war on Iran, with Republicans continuing to stand behind the administration as the conflict approaches a key 60-day deadline .