I think in the end, it was more the GOP members of Congress that did that, they never had President Bush's back.
I disagree. The problem was that they drank the kool-aid of 'compassionate conservatism' which translates to 'big government conservatism' which is neo-conservatism and is the kin of liberalism.
The House GOP showed some life by originally resisting the theft of middleclass wealth to give to Bankers. In the end they too showed that they were not conservatives but big-government liberals.