Adam Serwer had a good analysis of this in the American Prospect; I popped it in the overnight links last night, but here it is:

When Jon Stewart Fails.

There is an unexpected silence in the liberal blogosphere after last night’s highly anticipated Daily Show episode, in which Jon Stewart hosted John Yoo, the author of many of the Bush administration’s torture memos and one of the people most responsible for giving legal sanction to the practice of torture. That’s probably because Stewart found himself completely outmatched by a charming, tactful Yoo who seemed far better prepared to defend granting virtually unlimited powers to the executive branch than ever before. Put simply, Stewart failed to make Yoo look like he had done anything wrong. In fact, he made him look entirely reasonable. Stewart fares slightly better in the extended interview, but on the whole he was visibly out of his weight class.

Nails it, IMO.