I've mentioned repeatedly (since January) the implosion of the GOP, and it appears as if it definitely has been occurring over the last few months. Josh Marshall recently described it:
What we're seeing today are the cascading effects of the breakdown of Republican party discipline, beginning with the collapse of the president's popularity (especially the rather sudden recognition of that fact within Washington) and echoing out from there.
Moderate Republicans have toed the Bush line because they've believed he could protect them, as indeed he has. They don't believe that now. So a lot of them don't want to go into the election next year with ANWR drilling hanging over them.
They balk on the left and then in response the 'wingers on the other right refuse the compromises they've agreed to. Suddenly the whole thing starts to pull apart since there's no centripetal force, no organizing power to hold things together -- sort of like Hobbesian state creation run in reverse.
The recognition has sunk in: The president is unpopular and weak. And it's every Republican for him or herself.