This guy had it exactly right:

The polls show that for every "life-long" Democrat who teaches at a liberal arts college and thinks they are insulated enough from the economic and political shocks sure to result from massive deficits and pre-emptive wars to vote for Bush, there are more Republicans who have realized that their fiscal conservativism and reticence to get embroiled in foreign wars has been comprehensively and arrogantly repudiated by the person they thought was their standard-bearer.