He's still young and naive. In his dreams he wants to become somebody like his alter-ego (Al Bundy) with an option to work as Dubya's bodyguard (I'll bet he'd take a bullet aimed for "W" without a blink). His personality was shaped by both his parents an the neighbourhood he grew up and by FOX NEWS.
There is no way we could change his views at this point of his life. Some people - especially young people - need to stick to few "stable" things in life, some sort of axioms that found the basis of their thinking. Proving they're wrong would destroy these "foundations", it would destroy their present image of the world and literally shake their psyche.
Think of a stalwart religious person - or about a fanatic, if that's easier to imagine - if we'd be able to prove that their god does not exist, it would destroy all their beliefs, policies, philosophy etc. Short trip to suicide, paranoia or total stagnation in their life - take your pick.
Therefore jimbo is not defending Bush Jr, he's defending his world, the world he closed himself inside.
*StarTrooper3000 owes me 3000 Euro for this thorough analysis*
