There's a reason.

Atrios says:

There's this sense that at any moment the damn will burst and they'll all be fighting over who hates Bush the most, but it hasn't happened yet.

You could find many reasons for why that won't happen. The one I'm currently leaning towards is a faith that Bush will be right and everything will be cool, so they can shove it in the Democrats face. And also a fear that if most of them change in such a public forum that the MSM will castrate them for being 'Flip-Floppers'. Which is amusing because I don't think the MSM will ever call any republican for being a 'Flip-flopper'.

I would go even further and suggest it has to do with their internal psychology and how it relates to how religious they are, but that would be mere speculation and would open me to flames.

Maybe sometimes next week.