Benefit Of The Doubt?

Andrew Sullivan's coverage of the Harriet Miers nomination has been pretty good, but this requires comment:

In general, I have always given presidents the benefit of the doubt on judicial nominees. I do again here - but want to see how Miers performs in the hearings. If she's really incompetent, we'll find out and she should be cashiered. But if she's just a meticulous nit-picker who believes that courts should intervene in politics as little as possible, why not vote for her? It's not as if she'd be the first mediocre crony in the court's history.

Although I'm not a fan of the sorts of cynical what's-good-for-the-Dems-is-good-for-the-country type arguments that Sullivan toys with in the rest of the post, it's the idea that Miers' confirmation hearings will shed any light on her fitness for the Supreme Court that needs to be combated. Sure, if she makes an absolute ass of herself---the odds against this are presumptively high, but if---then okay, lesson learned. What's much more likely, however, is that she'll do serviceably well. There are three reasons why:
1) Taking a cue from John Roberts, she won't give substantive answers;
2) The MSM have set expectations so low, that she would, in fact, have to give answers that would flunk in an elementary school civics course in order not to exceed them;
3) Media-driven confirmation hearings are not a setting in which prowess or competence in con law can be demonstrated---such a demonstration requires the years of training, writing, and theorizing that, e.g., Roberts had under his belt so as not to scare anyone with his contemptuous non-responsivenes; moreover, there is maybe one senator (Feingold, duh) capable of asking a question that could yield an insightful answer from a nominee with some, um, insight into constitutional law