This is the best news I’ve heard since the New York Times’ initial article on NSA surveillance. According to a Financial Times story carried by
MSNBC, a DoJ official has said that the Department of Justice has launched an investigation to identify who leaked the information.

    Earlier today. the Justice Department said it was opening an inquiry into “the unauthorised disclosure of classified information related to the NSA (National Security Agency)” but gave no further details. The investigation is expected to focus on information disclosed to the New York Times, which first reported the eavesdropping.

Bloomberg reports that Bush didn’t request the investigation. At a press briefing held at the President’s ranch in Crawford, White House spokesman Trent Duffy said Bush was informed of the investigation today and added that

The leaking of classified information is a serious issue. The fact is that al-Qaeda’s playbook is not printed on Page One, and when America’s is, it has serious ramifications.

The New York Times says that the investigation “apparently began in recent days following a formal referral from the N.S.A. regarding the leak, federal officials said on condition of anonymity.”

Civil liberty advocates were quick to respond:

President Bush broke the law and lied to the American people when he unilaterally authorized secret wiretaps of U.S. citizens. But rather than focus on this constitutional crisis, Attorney General Gonzales is cracking down on critics of his friend and boss. Our nation is strengthened, not weakened, by those whistle-blowers who are courageous enough to speak out on violations of the law.

. . . the priority at this point for the Department of Justice should be the appointment of an independent prosecutor to determine whether federal wiretap laws were violated” by the N.S.A. program.

Earlier this week, John Miller, an FBI spokeman, said that a letter had been sent to agents working in counterterrorism and intelligence warning them that, despite the public acknowledgement of the NSA program by the President, it remains classified and should not be discussed. Miller said the letter was sent by Gary M. Bald, executive assistant director for counterterrorism and counterintelligence, after agents received inquiries from local officials and others and sought guidance on how to respond.

There are several laws that can be invoked against a government employee who knowingly reveals classified information. One statute applies specifically to the NSA.

CNN adds that the leak investigation is expected to be handled, as is standard, by Justice Department prosecutors and FBI agents and that DoJ officials would not say when the investigation began.

UPDATE From the Washington Post:

    The Justice Department’s decision to reveal the opening of a criminal investigation is rare, particularly given the highly classified nature of the probe.

    Leak investigations generally begin with a referral to the Justice Department by the agency in question—in this case the NSA —which prompts a preliminary inquiry by prosecutors to determine whether a crime has been committed. The opening of a criminal investigation signals that prosecutors believe that laws barring disclosure of classified information by government officials were broken. It is likely to be a full-blown probe involving FBI agents and Justice investigators.

    The American Civil Liberties Union, which has argued that a special prosecutor should be appointed to determine whether Bush violated federal wiretapping laws, called the leak probe an unwarranted attack on whistle-blowers. “Attorney General Gonzales is cracking down on critics of his friend and boss,” said ACLU Executive Director Anthony D. Romero.

UPDATE 2 I either missed this or it was added later to the Washington Post’s article:

    In another recent case, the CIA general counsel’s office notified the Justice Department in November that classified information had been disclosed in a report by The Washington Post on the existence of secret “black site” prisons in Eastern Europe and elsewhere.