War with Iran?

William Polk, over at Juan Cole's blog, tells us that U.S. News and World Report thinks Bush is preparing to attack Iran.

Earlier discussions of air attacks on Iran seemed to suggest that March and April were the optimal months for such attacks (I've forgotten why if I ever knew), so we may not have long to wait.

Question: How would this affect the presidential race? I suspect Bush & Co. would think it would help McCain, but who knows? I suspect it would be very, very unpopular with a very, very large segment of the population. But, once at war, Americans tend to rally round the flag.