The blogosphere has long speculated about the benefits to the Bush "administration" of keeping Alberto Gonzales on board as Attorney General. Was it that he was so completely, personally loyal to Bush? Was he a firewall against the direct taint of scandal? Did he simply "know too much?" (God, it's really hard to even say that.)
One political side effect of letting Gonzales go is that it takes away the biggest target in reference to whom Members of Congress, political columnists, candidatesand others were willing to discuss "the I-word" -- impeachment.
The politics of impeaching a president (or even a vice president, for some reason) are such that most people just don't want to touch it. But some of them had gotten comfortable with the idea of impeaching Gonzales, and though it was a long, long way from becoming a reality its discussion in the media and in Congress couldn't have been all that pleasant a prospect for the White House, which had to have known that Gonzales was really a stand-in for the top bananas. Not that Gonzales himself didn't deserve it in his own right (and still does, resignation or no), but there it is.
So far, Gonzales' departure does not appear to have lessened the fervor for getting to the bottom of the various scandals in which he was embroiled, and there are many. This is good news, of course. But we have yet to see whether the Congressional committees still waiting for compliance with subpoenas issued to the Department of Justice will find their schedules disrupted once again by requests for still more extensions, this time due to the upheaval in the Department caused by Gonzales' departure, and/or the time needed for his replacement to "get up to speed" with the investigations. Has Gonzales' departure reset the play clock, while continuing to eat up valuable game time?
At bottom, most of us are forced to admit that all of the things for which Gonzales ought to have been impeached were done at the direction of the White House. That being the case, it's very difficult to say exactly why it was Gonzales who deserved impeachment, but not the president. Well, it's logically difficult to say, but not politically difficult.
For as long as Gonzales held on (or Bush Cheney allowed him to, anyway), the only impeachment talk official Washington would tolerate was that about him. Now that he's gone, impeachment advocates are left looking squarely at Bush and Cheney again. And while this poses no particular problem for such advocates, will they be able to bring along those who preferred the less controversial nature of calling for Gonzales' impeachment? The answer is likely no.
So while the prospect of impeachment can't nearly be said to be the primary motivation for the resignation (it doesn't explain the timing, for instance, since Gonzales could certainly have held on longer), it's not a bad fringe benefit if you're even remotely worried about impeachment's "respectability creep" inside Very Serious Washington.