That just ignores domestic political reality. We just had the Dems in the House pass an appropriations bill that requires us to leave Iraq next year. Do you really believe that the US would launch a war against Iran to free 15 British sailors? The Dems have already sent a shot across Bush's bow warning him not to initiate a war with Iran without Congressional approval.
And you have you have to figure out the long term consequences after you pull the trigger.
Maybe the problem here is people need to actually call the Democrats bluff. The Dems, in the US House, just pulled a stupid PR stunt they KNOW the US Senate is going to kill dead. Rather then run scared of them, the President should simply call their bluff. Make them actually put their votes where their mouths are. Right now the Democrat Leadership is in the same place the Iranians are. Their actions are having NO consequences so they think they can get away with it.