[Editor's Note: Kathy Olmsted is back as our guest, and she's more cloak-and-daggerific than ever.]

On this day in 1994, Aldrich Ames pleaded guilty to giving secrets to the Soviet Union and later Russia. He was the highest paid spy in U.S. history, the first CIA agent ever proven recruited by the KGB, and the poster child for espionage for profit.

Historians of intelligence often use the acronym MICE to explain why people spy: Money, Ideology, Compromise (as in blackmail), or Ego. Throughout the 1930s and early 1940s, the Soviet Union had recruited dozens of Americans who spied because of ideology. They didn’t get paid to spy; in fact, they paid for the privilege, in the form of Communist party dues.

But for Ames – and for others in his generation of spies — it was all about money. In 1985, as a CIA officer assigned to Soviet counterintelligence, Ames knew the names of all the Soviets who were secretly working for the CIA. He was in an ideal position to sell these names to the KGB. Angry, unstable, and in chronic need of money, Ames boldly entered the Soviet embassy in Washington in April 1985 and delivered a letter describing some Soviets who had offered to spy for CIA. The delighted KGB paid him $50,000. Two months later, he turned over the names of more than ten Soviets working for the CIA and FBI in return for $2 million. Some of these CIA sources were killed; others vanished.

As their assets disappeared, CIA officials knew that the agency had been penetrated and launched an investigation to uncover the mole. Nevertheless, Ames continued his espionage activities for nine years. When he was arrested in 1994, members of Congress and the media asked in astonishment how the agency could have missed all of the warning signs. Ames drank heavily, received poor job evaluations, parked his Jaguar in the CIA parking lot, and paid cash for a half-million dollar house. Yet agency officials resisted for years recognizing that one of their own had changed sides. Finally, in 1993 CIA officials turned the case over to the FBI, which succeeded in catching Ames a year later. In return for cooperating with CIA debriefers, Ames received a life sentence rather than facing certain execution.

The Ames case, with its revelations of treachery and incompetence, demoralized the agency. CIA chief James Woolsey ordered three different investigations into the causes of the fiasco, but still could not save his job. He resigned at the end of 1994. Both the Senate and House Intelligence Committees issued detailed reports that, in the words of the Senate report, criticized the CIA’s “gross negligence” in the case.