The sequence of events leading to the resignation of Attorney General Alberto Gonzales, per media reports, goes like this: White House chief of staff Joshua Bolten sends out a directive to senior Bush officials telling them that if they are not planning to stay until the end of the administration, January 2009, then they need to depart by September of this year. Gonzales, under siege from Democrats in Congress over his handling of the firing of U.S. attorneys and his role in wiretapping and other national security hot-button issues, decides he can’t promise to go the distance and announces he is leaving. His friend and patron the president seizes the occasion to denounce the AG’s critics, railing against “months of unfair treatment” of Gonzales, his “good name . . . dragged through the mud for political reasons.”

Now, you would certainly be accurate in calling this a departure under fire. The adjective “embattled” has been inseparably attached to the compound noun “attorney general” at least since Democrats took control of Congress in January. But was the external pressure all that led Gonzales to quit? Or was there an internal political calculation to the departure?

There was always a political case for Gonzales staying, and it was well understood in the Bush White House: If Gonzales doesn’t leave, you don’t have to worry about the confirmation of a successor. If he does and you do, then you are subject to a process of political arm-twisting by Senate Judiciary Committee chairman Patrick Leahy and a supporting cast including the wily Chuck Schumer. Any nominee for attorney general would be in for a brutal grilling, accompanied by demands for right conduct in office, as Democrats define it. What price confirmation?

Perhaps the appointment of a special prosecutor to look into the firings of the U.S. attorneys? In Watergate times, Elliot Richardson had to pledge as much in order to be confirmed as Richard Nixon’s attorney general–more, he had to come up in advance with a name acceptable to Democrats on the Judiciary Committee (Archibald Cox). The political damage done to the Bush administration by the appointment of a special counsel to look into the leak of Valerie Plame’s covert status at the CIA was bad enough. The notion of setting loose a special prosecutor on the Justice Department and the political section of the White House in the waning months of a weakened presidency ought to have given, and by all accounts did give, officials a bad case of prospective heartburn.

So there was a certain raw logic to keeping Gonzales in place, even though most Republicans besides the president himself were singularly unimpressed with Gonzales’s performance under oath on Capitol Hill on the U.S. attorney firings, and not a few were genuinely appalled by testimony in May this year about his attempt as White House counsel in 2004 to muscle Attorney General John Ashcroft in Ashcroft’s intensive-care hospital room to reauthorize the White House’s terror surveillance program. The political calculation dovetailed with Bush’s loyalty to his old friend to reinforce the case for standing by Gonzales.

Has anything changed? Well, in fact, yes, though likely not Bush’s personal loyalty. First, the administration is a little stronger politically than it was in the first months of the year. The Watergate scenario for capitulation to the demands of the Judiciary Committee Democrats requires a political collapse more drastic than what this administration has suffered.

Second, whatever commentators now say, the departure of Gonzales was not inevitable. The widespread awareness in Washington of the political stakes in the event of his departure mitigated against the expectation he would leave. Senate Democrats thus didn’t expend much effort laying the ground for a broader post-Gonzales independent counsel investigation. The overall thrust of the Democrats’ attack remained on Gonzales himself, which they may come to regret.

In late July, four Democratic senators including Schumer wrote Solicitor General Paul Clement (because Gonzales and his deputy are recused on this matter) requesting the appointment of “an independent special counsel to determine whether Attorney General Gonzales may have misled Congress or perjured himself in testimony before Congress.” Though Leahy prudently did not sign that letter, he has been busy. On August 16, he wrote Justice Department Inspector General Glenn Fine asking him to “investigate and evaluate potential misleading, evasive, or dishonest testimony” by Gonzales. Only this week, days after the announcement of Gonzales’s resignation, Fine provided Leahy with his answer: The office of the inspector general “has ongoing investigations that relate to most of the subjects addressed by the Attorney General’s testimony that you identified.”

The political implications of the Fine letter are large. Clement would have no reason to grant Schumer et al. their wish for a special counsel as things stand. But a negative report from Fine would open an entirely new chapter. If the IG report finds indications of wrongdoing and the acting attorney general has ducked the issue, the political pressure to let a special counsel sort it out becomes immense. So it is that as a result of Democrats zeroing in on the person of the attorney general, Alberto Gonzales has gone from a position as bulwark against the appointment of a special counsel under the pressure of confirming a successor, to a position in which he poses the greatest risk of such an appointment as a consequence of the political pressure from an internal Justice Department investigation.

So Gonzales’s departure may be timely after all. As to what comes next, indications are the White House understands that there has to be a litmus test for the nominee to succeed Gonzales: namely, no commitments in the confirmation process to appoint a special counsel (or to overturn the position the administration has taken on executive privilege to shield White House officials from scrutiny under oath in congressional hearings). Someone coming in fresh with this attitude is fairly well-positioned to maintain that he or she has no conflict and is perfectly capable of supervising any ongoing investigation into the former attorney general’s conduct.