Patrick Fitzgerald has been slowly, but surely trudging ahead with the investigation into the leaking of the identity of CIA agent Valerie Wilson -- A.K.A. Valerie Wilson. So far, both Karl Rove and Scooter Libby have been tied to the leak, and more information is certain to be on the way.

In a new development in the case that the AP's Mark Sherman reports, President Bush has placed a new man in the position to oversee Pat Fitzgerald's investigation.

David Margolis, a lawyer at the Justice Department for 40 years, was named Friday to oversee a special prosecutor's investigation of who in the Bush administration disclosed the name of an undercover CIA officer.

Margolis, whose title is associate deputy attorney general, is taking the place of Deputy Attorney General James Comey, whose last day of work was Friday. Comey will be Lockheed Martin's new general counsel.

Comey made the designation of Margolis. Attorney General Alberto Gonzales has stepped aside from the probe because he was White House counsel when Valerie Plame's name was leaked in 2003 and he has testified to the grand jury investigating the unauthorized disclosure.

Comey gave broad discretion to U.S. Attorney Patrick Fitzgerald of Chicago when he was appointed to investigate the leak in December 2003. Margolis is not expected to alter Fitzgerald's mandate in what are likely to be the final months of his investigation. The grand jury ends its term in October.

Sherman says "Margolis is not expected to alter Fitzgerald's mandate," and I have no reason not to believe him. Indeed, Margolis has been with Justice for at least forty years. If, however, Margolis intends to inhibit Fitzgerald to any degree -- as one could infer from this late Friday announcement (note: a possibility, not by any means a probability) -- today will go down in history as just another replay of the Saturday Night Massacre when President Nixon attempted to undercut the Watergate investigation.