I think this is spot-on:

Nothing here that hasn’t been said in one form or another elsewhere, but this is the root of the problem with Miers:

Bush and Rove have spent the last five years doing everything in their power to hide the true conservative agenda from the American people. We get shit like "Clean Skies Initiative", "Healthy Forrest Initiative" and "Death Tax". Heck, Frank Luntz has written a whole manual on how to use language to hide the plain-English definition of their policies.

Furthermore, Bush has done everything to hide the costs of their conservative ideology — passing budgets that exclude budget items like the cost of the war and so on.

So after five years of sitting in the shadow, waiting for the president and Republicans to trumpet conservative principles to high heaven, he delivers, instead, two stealth candidates. This was supposed to be their "coming out" party, and yet Bush refuses to let them out of the closet. Republicans are losing ground with the American people, as the public becomes increasingly intimate with the side effects of Republican mis-governance. The last thing they need is the last fictions of the conservative agenda, masked by rhetorical devices and Friday-afternoon disclosures, trumpeted for all to see.

The conservative agenda is not a dominant ideology, otherwise they wouldn’t be so loath to give it to us unvarnished. It is a minority ideology. Yet the conservative yahoos don’t get it. They think they’re in the majority and can’t fathom why Bush won’t let them party out in the open.

So therein is Bush’s dilemma. Sabotage the conservative movement by announcing its principles with a bullhorn (precisely what a Prescilla Owens would’ve done), or suffer conservative discontent by keeping them locked up in the basement.

Bush chose the latter.