I am the son of a geophysicist. As such I know a wee bit (emphasis on “wee”) about plate tectonics. Plate tectonics is the theory that best explains how the continents came to be through slow but inexorable movement. [Note: my father reads the blog so perhaps he will give a better explanation – Dad?]
In any event, the key is that the plates shift slowly but the shift cannot be stopped.

There is a tectonic shift happening separating evangelicals from Republicans. It is massive but it is slow. The results may not be seen in 2008 (though I expect they will be seen) but they will in the decade to come.
Evangelicals are increasingly tired of the Republican party. And they feel used. I know this based on countless conversations, the lack of giving to republican congressional and presidential candidates, and the continued revelations of Republican hypocrisy.
For decades evangelicals have been told that the Republican party is the party of morality and of God. Evangelicals have had the sense that the Republican party was almost a political church. For decades evangelicals have given time and money to Republicans in the absolutely good-hearted belief that they were going to create a better and safer America. No evangelical can believe that any more. No evangelical should.
This does not mean we will see conservative Christians flocking to the Democratic party although some will. I think we will see a disengagement – perhaps not of voting but of money. Christians understand what it is to tithe to a good church and that they are stewards of the money God has entrusted to them. They aren’t going to throw much money to politics.