Philiosophically this is easy.  Everything.

But I want to talk about why the political machine is breaking down.

First, the GOP views their time in power as profit taking.  They make no attempt to run an effective, constructive government.  They simply stuff their pockets as fast as they can, taking as much as possible before the shit storm that washes them away.  Look at 1920-1932 if you don't believe me.  In a weird way, this was part of the plan.

Second, I think their inability to move to the center is partly because they have a serious problem with their base.  In that it doesn't really like their candidate.  McCain is viewed as liberal, not particularly religious and indifferent at best on tax cuts.  This will not generate big voter turnout.  You run to the center to win independents but you need the base to turnout to win as well.  McCain hasn't figure out a way to do both.  He might come up with one or he might not.  It might be impossible.

Third, and this is related to the second point, the GOP has lost all control of the Reagan coalition.  The four pieces of the Republican party are falling apart.  In 1968, Nixon married the racists to the war hawks and tax/regulation-haters to create the modern Republican Party.  In 1980 Regan brought in the Fundamentalist Christians.

Now, with a war hawk candidate, the tax haters know their part but the Jesus freaks are lukewarm and might not turn out, which is disastrous for the party because they comprise the most people.  War hawks and tax/regulation haters supply money and clout, not actual bodies.  A bigger problem comes from the racists.  Sure, they are going to vote like crazy against the black guy but they had (possibly fatally) wounded the party by making immigration an issue.  Recall how Bush, Cheney and the GOP establishment reacted to his call for a wall and mass deportation.  They were horrified.  The reason was twofold.  First it hurt the steady supply of cheap, benefit free labor large corporations  thrived on.  but that had little to do with electoral politics.  More importantly, it polarized and agitated the hispanic voters.  This is a massive (as much as 20%) and fastest growing voting block in the US and one Bush had done an amazing job pulling over to the right. (He split the brown vote in 2000 and 2004).  In 2006 they lost that vote bad and now McCain can either piss off the racists or go begging to the brown folks which probably won't work anyway.

Significantly taking the hispanic vote from 50/50 to say 60/40 will cost the GOP the southwest and weaken them in their most important stronghold- Texas.

This is why I believe the party has fallen apart and why McCain is stuck running to the right almost three months after winning the nomination.