When Josh Marshall takes note, a good conspiracy theory is elevated to something worth worrying about.
For my part, I would expect a pre-election terrorist attack to heighten Bush's chances of re-election, not lower them, for the following reasons:
1. American people continue to be far more supportive of the Iraq invasion than Spaniards ever were.
2. The Spanish voted out the incumbent party not just because of the terrorist attack, but primarily because the incumbent party tried to blame the violence on Basque separatists, even in the face of the evidence.
3. Partly because we have the recent events in Spain as an example, I think Americans are extremely concerned about doing the right thing and not "giving in", even to the extent that it would become their sole motivating factor. At the same time, Bush/Cheney has been highly successful at insinuating their subtext.
So why would Bush/Cheney want to postpone the election? Additional time would allow Americans to think instead of react blindly. Do they have so little faith in themselves and in the country's perceptions of their abilities to "keep us safe"?
Are they just hedging their bets in case the landscape changes and a postponement would work in their favor? (This is the most likely, I think, it has the same feel as certain actions taken in the 2000 post election period.)
Or is there something more nefarious afoot?
In my book, the only legitimate reason for postponing (or cancelling) national elections would be if a significant portion of Americans were physically unable to vote, whether because no polling places could be set up or whether people couldn't get to them. I'm not sure what might constitute a "significant portion", though, surely every election day there are minor disasters preventing small numbers of people from voting. Do we have no guidelines for how to handle a major natural disaster on or immediately before election day?
I continue to advocate this stance, even though I believe a postponement would be advantageous to the Dems.
Update: A belated thought. Could it be that Bush/Cheney are looking at what happened after 9/11? In that case, Bush's approval ratings went up significantly in the weeks after the disaster. For example, the CBS/New York Times polls shows approval ratings of 72% on 9/11-12/01 and 90% on 10/8/01. Other polls so lesser but still statistically significant rises.