An open “what if” question

In light of rumblings about contingency plans to postpone elections because of terrorist attacks -- and the administration's rapid dismissal of that idea -- there is an interesting political hypothetical to consider. What would be the electoral impact of a spectacular terrorist attack? Would it benefit Bush or Kerry? [Define "spectacular"--ed. An event that would force the networks to interrupt their regularly scheduled programming.] This has come up in a number of conversations, and the answer I keep hearing is that it would benefit George W. Bush, because of a) an immediate rally-round-the-flag effect; and b) a belief that Bush places a higher priority on the War on Terror than Kerry. I suppose this is possible, but I confess to puzzlement. Wouldn't another spectacular attack suggest that the administration has not made significant progress in the War on Terror? That would be my first thought. However, this would hardly be the first time I've misread public reaction to an event -- or, rather, that my reaction was the minority viewpoint. So, to repeat/rephrase the question: would a spectacular terrorist attack that took place close to Election day help President Bush or Senator Kerry? I look forward to your thoughts on the matter. UPDATE: A second question: should a spectacular terrorist attack that took place close to Election day help President Bush or Senator Kerry?