The 'I' word

The recent spectacle of Republican Congresscritters marching out to hold a press conference as the House issued contempt sanctions for Miers and Bolten might be dismissed as the usual high spirits of our native criminal class. Scott Horton, however, is thinking differently:

Moreover, if the Justice Department’s report implicates not just Rove, Miers and Bolten, but also Bush in the decision to fire for improper reasons—a conclusion which is now looking extremely likely—then it will be up to Conyers’s committee to press the investigation forward. In so doing, he is entitled to conduct hearings on the footing of impeachment. If he does, the executive privilege objection interposed by the White House and backed in another Constitution-defying opinion of the Attorney General, would not apply.

Impeachment is the direct means to confront Bush's defiance of Congress. As Scott says, claims of executive privilege could not be made. Unless, of course, Bush is willing to open the biggest and perhaps last constitutional crisis of all time.

What I don't understand is, why now? Congress has been sitting on their pudgy little hands for over a year with many reasons to demand accountability. What has changed?