Why the Republicans Resist Compromise - Nate Silver

http://fivethirtyeight.blogs.nytimes.com/2011/07/07/why-the-g-o-p-cannot-compromise/

This is perhaps the best analysis of the current crisis that I've read yet. It gives the reasoning behind why the GOP would so violently resist any appearance of backing down. Their "spine" so to speak, the conservatives, have now become the entire body. Moderates and independents have more or less left the party, or the party left them, leaving only the right wing. This can benefit a party in an election like 2010 when the conservatives were the most likely to turn out. However, and this is crucial, the equation reverses in a presidential election when voters of all stripes turn out. This is the problem present in the Republican party right now: the candidates must appeal to the right wing in the primaries but that appeal is a turn-off in the general election. Hence the Romney-Bachmann dilemma.
Nate predicts that if conservatives turn out in a 3-1 ratio over moderates in the Republican primaries, Bachmann will squeak by. If the ratio is only 2-1, Romney will eke it out. Something to follow going forward.