Spy missions

Top 10 most damaging spy missions in history

The Espionage Act of 1917 defined espionage as the notion of obtaining or delivering information relating to national defense to a person who is not entitled to have it. The Act made espionage a crime punishable by death, but there are always men and women willing to risk it — for country, for honor, or maybe just for some quick cash.

Whether they infiltrated the enemy's ranks or sweet-talked the details out of careless persons who ignore all those "loose lips sink ships" posters, these are the most notorious spies with the most successful espionage missions in history, ranked by the operations they disrupted, the damage they dealt, and the odds stacked against them.

Aldrich Ames is a 31-year CIA veteran turned KGB double agent. In 1994, he was arrested by the FBI for spying for the Soviets along with his wife, Rosario Ames, who aided and abetted his espionage. Following his arrest and guilty plea, Ames revealed that he had compromised the identities of CIA and FBI human sources, leading some to be executed by the Soviet Union.

During a nearly year-long investigation into his subterfuge — and his subsequent trial — it was revealed that Ames had been spying for the Soviets since 1985, passing details about HUMINT sources, clandestine operations against the USSR, and providing classified information via "dead drops" in exchange for millions of dollars.

It was, in fact, the Ames' lavish spending that finally led to their downfall, but by then, he had already nearly destroyed the American intelligence program in the Soviet Union.

Ames is currently serving his life sentence, while his wife, as part of a plea-bargain agreement, served only five years and walked free.