I have a great deal of sympathy for Ed Kilgore's skepticism about impeachment. Given that there's not a decent prospect of success, the question of whether or not it makes sense for Democrats to embrace this idea amounts to a question of whether or not it makes sense as political positioning. And it's by no means obvious to me that it does make sense as political positioning. That said, once you have the Director of the FBI testifying before congress that the Attorney General of the United States has been lying to them as part of a broad coverup of an illegal spying operation, you're passed the point where impeachment talk is a fringe concern.
Which I why I have to register some dissent from Ed's view "the questions about the 'I-word' need to be honestly addressed, without the presumption that anything less is craven." At the end of the day, the argument Ed's making really is an argument from craveness -- it's the argument that Democrats should fear the results of playing with fire, not the argument that there are no crimes in this neighborhood. Fundamentally, I think the case for craveness has some merit, and I'm not scandalized that lots of politicians don't want to embrace it, but I'm by no means unhappy to see folks with safe seats talking about it. One way or another, investigations need to continue into the domestic spying program, into the US Attorney firings, into the Scooter Libby pardon, etc., etc., etc. and without prejudging the case one should say that insofar as hard evidence (which really is different from "good enough for journalism" evidence) of abuses of power keeps surfacing, that their ought to be consequences.
It's not, after all, as if Bush is reacting to the news that FBI Director Mueller "contradicted the sworn testimony of his boss, Attorney General Alberto R. Gonzales, by telling Congress that a prominent warrantless surveillance program was the subject of a dramatic legal debate within the Bush administration" by getting mad and sacking Gonzales or anything.