WASHINGTON - Looking back, John Kiriakou admits he should have known better. But when the FBI called him a year ago and invited him to stop by and "help us with a case," he did not hesitate.

In his years as a CIA operative, after all, Kiriakou had worked closely with FBI agents overseas. Anything for the FBI," Kiriakou replied.

But an hour into what began as a chat with two agents, he began to realize just who was the target of their investigation.

On Jan. 25, Kiriakou is scheduled to be sentenced to 30 months in prison as part of a plea deal in which he admitted violating the Intelligence Identities Protection Act by e-mailing the name of a covert CIA officer to a freelance reporter.

In more than six decades of fraught interaction between the agency and the news media, Kiriakou is the first current or former CIA officer to be convicted of disclosing classified information to a reporter.

Kiriakou, 48, earned numerous commendations in nearly 15 years at the CIA, some of which were spent undercover overseas chasing Al-Qaida and other terrorist groups. But he got mixed reviews at the agency, which he left in 2004 for a consulting job. Some praised his skills, first as an analyst and then as an overseas operative; others considered him a loose cannon.

Kiriakou first stumbled into the public limelight by speaking out about waterboarding on television in 2007, quickly becoming a source for national security journalists. When he gave the covert officer's name to freelancer Matthew Cole, he said, he was simply trying to help a writer find a potential source and had no intention or expectation that the name would ever become public. In fact, it did not surface publicly until long after Kiriakou was charged.

He is remorseful, up to a point. "I should never have provided the name," he said. "I regret doing it, and I never will do it again."

At the same time, he argues, with the backing of some former agency colleagues, that the case -- one of an unprecedented string of six prosecutions under President Obama for leaking information to the news media -- was unfair and ill-advised as public policy.

His supporters are an unlikely collection of old friends, former spies, left-leaning critics of the government and conservative Christian opponents of torture. Whatever his loquaciousness with journalists, they say, he neither intended to damage national security nor did so.

The leak prosecutions have been lauded on Capitol Hill as a long-overdue response to a rash of dangerous disclosures and defended by both Obama and his attorney general, Eric Holder. Neil MacBride, the U.S. attorney for the Eastern District of Virginia, hailed Kiriakou's conviction, saying: "The government has a vital interest in protecting the identities of those involved in covert operations."