A significant segment of the Religious Right has not been supporting Republicans for the proper reason - because Republicans will fight for freedom of worship against Democratic legislation that tries to curtail it. Rather, they have stayed on board in the hope that their beliefs would some day be written into law. Thus, there is anger at Bush for not doing enough to advance the social conservative agenda - they want laws passed, not speeches.
The grand coalition is fragmenting a bit.
I have not heard of social conservatives abandoning Bush, and being a social conservative, I should have gotten the memo.