I came across this passage in Haper's Magazine
. (Dr. Leon) Festinger explained that a committed believer, when faced with irrefutable evidence contradicting his belief - with what Festinger called a "disconfirmation" - would redouble rather htan diminish his efforts to defend his view. Stranger yet, the more harshly reality dealt with a belief, the more feverishly the believer would work to convert others.
The article was about "Peak Oil" and is a great read. I think this pasage goes a long way to explaining why otherwise sane people like Dave from First State Politics and Michael Castle would work so hard to defend Republicanism in general and George Bush in particular.