If the right really is deliberately spiking McCain, it's probably because it's the only chance for the far-right to keep their influence in the party. A victory for McCain, or a loss for a more conservative candidate, would signal a shift toward the center. But a loss for McCain can be blamed on being "too librul".
http://en.wikipedia.org/wiki/Keating_Five
Victory for the Keating Five!
Yeah so the conspiracy that I have come up with is pretty much that they want a Democrat to be elected so that it's a Democrat that has to raise taxes and pay for everything, and also deal with this shitty consequences of their shitty war. Then a Republican can come in and embezzle all the money and give it to the rich people again. Rinse and repeat!
Also McCain is not significantly against earmarks, he's just against earmarks that don't help him very much, which just makes him sort of an ASSHOLE really.
Take for instance uh well uh you know, the issue is CONSISTENCY not uh being different from Bush? Like privatizing social securi--wait, dammit! This is hard.