I would have thought this was simply obvious, but a few people at dinner thought it might be useful to make the point plainly. The Bush administration is considering airstrikes against Iran. Some people think the decision has already been made to do it. Most people think this isn't totally clear, but some folks inside the government want strikes and may win the fight. The options being seriously considered all involve, basically, launching a surprise attack. This means, among other things, a war without any serious basis in domestic or international law. No UN resolution, no congressional resolution, just an order from the President to the relevant military assets. There'll be vague gestures in the direction of this or that -- the crew that's argued the 9/11 Resolution repealed FISA and the 4th Amendment will argue that it authorized just about anything -- but basically they'll just be making shit up which isn't at the end of the day, a novel situation for them to be in.
The War Powers Act states that "The constitutional powers of the President as Commander-in-Chief to introduce United States Armed Forces into hostilities, or into situations where imminent involvement in hostilities is clearly indicated by the circumstances, are exercised only pursuant to (1) a declaration of war, (2) specific statutory authorization, or (3) a national emergency created by attack upon the United States, its territories or possessions, or its armed forces." Meaning, in other words, that simply launching an attack on Iran would be illegal. Dick Cheney has, however, argued for decades that the War Powers Act is unconstitutional, so this isn't going to stop them. You'll be able to file an after-the-fact lawsuit, if you like, but that's not going to have much practical impact.
Matthew Yglesias is a former writer and editor at The Atlantic.