She was given a polygraph examination, confronted about answers given to the polygraph examiner and confessed, the government officials said. On Thursday she was stripped of her security clearance and escorted out of C.I.A. headquarters.

As to the subject matter:

Intelligence officials speaking on the condition of anonymity said the dismissal resulted from "a pattern of conduct" and not from a single leak, but that the case involved in part information about secret C.I.A. detention centers that was leaked to The Washington Post.

This is all part of Bush's latest plan to get heavy with leakers:

The dismissal of Ms. McCarthy provided fresh evidence of the Bush administration's determined efforts to stanch leaks of classified information. The Justice Department has separately opened preliminary investigations into the disclosure of information to The Post, for its articles about secret prisons, as well as to The New York Times, for articles last fall that disclosed the existence of a warrantless domestic eavesdropping program supervised by the National Security Agency. Those articles were also recognized this week with a Pulitzer Prize, awarded to two New York Times reporters.

Right-wing bloggers will no doubt make this a focal point of the story:

Public records show that Ms. McCarthy contributed $2,000 in 2004 to the presidential campaign of John Kerry, the Democratic candidate.

But, isn't the bigger issue why is it okay for Bush and Cheney to decide to instantaneously declassify portions of the NIE report so Libby could leak it to Miller, or Rice to leak classified information to AIPAC lobbyists (which she denies) but not okay for a whistleblower to leak to a reporter?