Thirty years ago, the murder of Richard Welch, then the CIA station chief in Athens, shocked the nation. The eventual result was the Intelligence Identities Protection Act, the statute governing the current investigation into whether Bush administration officials illegally revealed to reporters that Valerie Plame worked for the CIA.

Six months before he was slain by masked gunmen outside his home, Welch was among several purported CIA operatives named by a left-wing U.S. magazine called Counter-Spy, which ceased publication following his death.

Then-CIA Director William Colby attributed Welch's assassination to his identification in Counter-Spy, co-founded by a renegade former CIA officer, Philip Agee, who had worked for several years in Latin America before resigning from the agency and moving to Cuba.

But Agee was not the first to publish Welch's name. Seven years earlier, Richard Skeffington Welch was identified as an American spy in a small hard-bound book, "Who's Who in CIA," published by two Soviet-bloc intelligence services in 1968.

A senior U.S. official acknowledged that major opposition agencies and friendly intelligence services are likely to know the identities of virtually all U.S. intelligence officers serving overseas, especially those, like Welch, who pose as American diplomats.

"But," he added, "the terrorists don't."

Despite Welch's name being published in the Soviet-bloc book, Counter-Spy became the focus of the congressional debate on the Intelligence Identities Protection Act. The statute, declared Rep. C.W. Young (R-Fla.), was aimed at "the Philip Agees of the world."

The IIPA, enacted in 1982, makes it a federal crime to intentionally reveal the identity of a covert U.S. intelligence officer. The maximum penalty is a $50,000 fine and 10 years in prison.

Two years after the IIPA became law, the CIA's Beirut station chief, William Buckley, was kidnapped by an Iranian-backed terrorist group, Hezbollah, which tortured him to death.

The IIPA offered no protection to Buckley, who had not been identified in "Who's Who in CIA," Agee's memoirs or Counter-Spy, but whose intelligence connections had become known during his prior service in Vietnam, Zaire, Cambodia, Egypt and Pakistan.

Despite the urgency that surrounded its passage, the IIPA has been used only once, in the 1985 case of a young CIA clerk in Ghana who pleaded guilty to disclosing the names of two local CIA officers to her Ghanaian boyfriend. The woman served 8 months of a 5-year prison sentence.