That's about the size of it

The real story behind the Miers nomination remains to be seen, but for my money, Ezra's got the gist of the matter:

[I]n the end, Bush really was a provincial, uninterested power-amasser. He wanted a Texas crony and, since conservatives deep-sixed Gonzales, Miers was the logical fallback. There's no political upside to the pick but then, for the reelected Bush, there's really no downside either. Where the fuck are congressional Republicans gonna go? What's the Christian Right gonna do? Get behind a neanderthal like Roy Moore so the country can elect a liberal like Hillary Clinton? Let 'em try. Bush has 'em by the balls. The Christian Right's influence comes from control over the Republican party, but since Bush shows little evidence of caring about the long-term health of his party, they've got nothing on him. Nobody does. He can pick who he wants.

And so he did.

That sounds right to me. Now that he can't get reelected, there's far more incentive for Dear Leader to stock powerful positions with cronies than there is for him to shore up the flagging loyalties of various conservative factions. At the end of the day, he could care less about the GOP - it's his own power and influence he's looking out for now.