4. Mildred Gillars, AKA “Axis Sally”

Born in Portland, Maine, Mildred Gillars left for France at the age of 29 hoping to become an actress but becoming a Parisian fashion model instead. There she met and eventually married Max Otto Koischwitz, director and broadcaster of Nazi propaganda during World War II. Moving to Berlin, she became a disc jockey under her husband’s broadcast channel. Known to Allied soldiers as the “Bitch of Berlin,” Gillars became popular among American troops. “Her accent and her sweet, sexy voice and because she played the latest hits, interspersed with crude propaganda (Why fight for the communists? Why fight for the Jews? Etc.) that gave the men a laugh,” writes Stephen Ambrose.

However, because of the Double Cross System, “Axis Sally” also interspersed her commentary with facts that could be chilling to the men. Sgt. Gordon Carson of the U.S. 101st, stationed in Aldbourne, England, recalls one such incident in which Axis Sally remarked “Hello to the men of Company E, 506th PIR, 101st A/B in Aldbourne. Hope you boys enjoyed your passes to London last weekend. Oh, by the way, please tell the town officials that the clock on the church is three minutes slow.” Designed to inspire homesickness and fear, Gillars’ grisly broadcasts eventually got her convicted for treason.

Serving 12 years in a West Virginia federal reformatory, Gillars was released in 1961 and went on to teach music in Columbus, Ohio. She died at the age of 87 in 1988.

3. Aldrich Ames

Aldrich Ames, a counterintelligence officer in the CIA’s Soviet division, has earned the dubious distinction of perpetrating the most expensive security breach in CIA history

Despite being deemed mediocre by his superiors, Ames was nonetheless an overachiever by Moscow standards. From 1985, until he was caught nine years later, Ames sold some of the CIA’s deepest secrets to the KGB, continuing even after the collapse of the Soviet Union in 1991. During his traitorous run, Ames betrayed 12 secret agents “working for the United States from within the Soviet Union and the Soviet bloc during the 1980’s,” writes the New York Times. “All were jailed and most were executed.”

“They died because this warped, murdering traitor wanted a bigger house and a Jaguar,” R. James Woolsey, the then Director of Central Intelligence, later stated.

A 31-year veteran of the CIA, Ames provided the Soviets with highly classified details about state-of-the-art technology used to count nuclear warheads and fiber optic cables that allowed to U.S. to hear communication connected to Moscow’s space facility, according to PBS.

Although the FBI caught on to Ames’ schemes in late 1992, it wasn’t until 1994 that the traitor was apprehended— one day before he was supposed to travel to Moscow on official CIA business.

Ames is currently serving a life sentence for espionage without the possibility of parole, telling CNN in 1988 that his motivations were simply “personal, banal, and amounted really to greed and folly.”

2. Harold “Jim” Nicholson

Rising rapidly through the ranks of the CIA, Harold “Jim” Nicholson was first posted to Manila, then Bangkok and Bucharest, and then finally to Kuala Lumpur, where he served as deputy station chief. It was there in 1994, in Kuala Lumpur, that Nicholson was recruited to work with the Soviet spy service, the SVR. He began to supply the Soviets with information shortly after starting his new post as an instructor at the CIA’s training facility, known as “the Farm.” For two years Nicholson leaked the bios of over 300 CIA trainees, many of whom were training for covert missions overseas. In addition, he sold to the Soviets assignment information for new CIA officers headed overseas for their first assignment. Michael Rochford, a former chief of the FBI’s counterespionage section, stated that “There are CIA officers who cannot be posted overseas in hostile environments even today because Nicholson gave up these people’s identities.”

Flags were raised in 1995 after Nicholson failed three polygraphs as part of his routine security update. According to the FBI affidavit, a computerized review indicated a .97 (out of 1.0) probability of deception on the following two questions: (1) Are you hiding involvement with a Foreign Intelligence Service? And (2) Have you had unauthorized contact with a Foreign Intelligence Service? In the affidavit, it was noted that during his third polygraph, the CIA examiner observed that Nicholson seemed to be trying to “manipulate the test by taking deep breaths on the control questions.” Nicholson was arrested in 1996, as he was boarding a plane to South Africa and Rome on a counterterrorism assignment. He was convicted of selling US intelligence to the Soviet Union and was sentenced to prison for 23 years and seven months.

Yet even after his conviction of treason, James was not finished. In 2011, the former CIA officer was once again charged with conspiracy to act as an agent of a foreign government and conspiracy to commit money laundering. Nicholson recruited his youngest son, Nathaniel to collect approximately $47,000 from Russian officials in Mexico, Peru, and Cyprus for his father’s previous spy work. Eight years were added on to his original 23-year prison sentence.

1. Benedict Arnold

His name has become synonymous with treachery in the American lexicon, and for good reason. Benedict Arnold, an American war hero and general, switched sides in the Revolutionary War in early 1779. Passed over for promotion, slowly going bankrupt (he lent his own personal fortune to Congress), and pessimistic about America’s chance of victory, Arnold began plotting to switch sides.

As the commander of West Point, Arnold gave the plans of the fortifications to Major John André and agreed to surrender the defenses in exchange for £20,000 (approximately $3 million today). When André was captured by Major Benjamin Tallmadge, he retained damning evidence of Arnold’s treachery. Arnold escaped along the Hudson on the HMS Vulture.

By the winter of 1780 Arnold was a brigadier general in the British army and leading raids through Virginia and Connecticut. Not only had he betrayed his fellow soldiers, Arnold was now leading British forces against the men he had once commanded. Ben Franklin famously penned that “Judas sold only one man, Arnold three Millions.”

Arnold was exiled to England after the British defeat, where he remained until his death in 1801.