How the Biggest Traitors In Military History Betrayed Their Countries

Photo Credit: 1. Underwood Archives / Getty Images 2. Pierce Archive, LLC / Buyenlarge / Getty Images 3. Thomas Joseph Tunney / Paul Merrick Hollister / Wikimedia Commons / Public Domain
Photo Credit: 1. Underwood Archives / Getty Images 2. Pierce Archive, LLC / Buyenlarge / Getty Images 3. Thomas Joseph Tunney / Paul Merrick Hollister / Wikimedia Commons / Public Domain

Military traitors are some of the biggest, most despised figures in history, but they’re also some of the most fascinating. It’s mind-boggling to consider how one could betray their own country and directly bring death to who were once their own allies. Some do it for the money, while others seek revenge. Many do it to satisfy their own narcissism. After changing sides, they typically aren’t accepted. However, if they can turn their backs on their own people, they can do it to anyone.

The following is a list of the biggest traitors in military history, beginning with the American Revolution.

Benedict Arnold

Illustration of Benedict Arnold handing papers to a seated John André
Photo Credit: Stock Montage / Getty Images

Benedict Arnold is one of the biggest, most well-known military traitors on our list. He was a brave and brilliant officer in the Continental Army during the US Revolutionary War. After proving his worth on a number of occasions and receiving brutal injuries, he felt other officers were taking some of the credit for his achievements and being favored over him for promotions.

Even though he was highly trusted by George Washington, Arnold became disillusioned with his side of the war. He defected to the British in 1780, after offering to hand over West Point, in return for a position as a general in the British Army. The British never captured West Point, but Arnold did betray the Continental Army, fighting against those he once led as a brigadier general.

In the United States today, Benedict Arnold’s name is synonymous with the word “traitor.”

Alfred Redl

Military portrait of Alfred Redl
Photo Credit: Hulton Archive / Getty Images

Alfred Redl, the second individual on our list of military history’s biggest traitors, was the head of the counterintelligence branch in the Austro-Hungarian Army, having pioneered counterespionage techniques. Between 1903-13, he secretly worked as a spy for the intelligence service of the Imperial Russian Army, using his position to hand over extremely valuable documents.

Over the course of his spying career, Redl gave the Russians the entire Austrian invasion plan for Serbia, military plans, doctrines, tactics and strength. He also used his position to provide the names of agents working as spies against Russia. Even worse, he sent some into Russia, only to then inform Russian authorities of their presence.

Redl is believed to be responsible for the deaths of tens of thousands of Austrians during the First World War, and he’s thought to have been part of the reason behind Austria-Hungary’s poor military performance during the conflict. In 1913, he was outed as a spy using his own techniques, at which point he took his own life.

Mildred Gillars

Mildred Gillars' mugshot
Photo Credit: Federal Bureau of Prisons / Wikimedia Commons / Public Domain

One of many American broadcasters to disperse German propaganda during the Second World War, Mildred Gillars broadcasted from Berlin under the moniker “Axis Sally.” Born in Portland, Maine, she moved to Dresden in 1934 to study music, after which she found work as an English teacher. Little did her friends and family back home expect her to work as a propagandist upon the outbreak of hostilities in Europe.

Gillars found work with German State Radio as a broadcaster in 1940. Throughout the conflict, she hosted three shows: Home Sweet Home Hour, which aimed to make American troops abroad feel homesick; GI’s Letter-box and Medical Reports, geared toward scaring those at home by reporting on American injuries and deaths in battle; and Midge at the Mike, where she made anti-Semitic remarks, verbally attacked US President Franklin Roosevelt and spread defeatist sentiments.

Gillars remained on the air until just two days before Germany surrendered. Her address was subsequently determined, and she was arrested in March 1946. After standing trial on eight counts of treason, she was found guilty and sentenced to between 10-30 years in prison. She was also ordered to pay a $10,000 fine. Gillars was released on parole in 1961.

Harold Cole

Harold Cole's mugshot
Photo Credit: Unknown Author / Daily Mail / Wikimedia Commons / Public Domain

A petty criminal, thief and fraud, Harold Cole is among the most notorious and biggest military traitors in British history. During the early years of the Second World War, he worked alongside the French Resistance, helping soldiers and downed pilots return to England via escape lines through German-occupied France. He was a prominent member, but ultiamtely betrayed members to the Gestapo in late 1941.

Cole handed over the names of 150 people working along the escape lines and/or for the French Resistance. Approximately 50 of them were either executed or died in concentration camps.

Over the course of the war, Cole was wanted by the British, Germans and French. He was killed in a gunfight with French police in 1946, after resisting arrest, and is now considered among the “most selfish and callous traitors who ever served the enemy in time of war.”

Robert Hanssen

Portrait of Robert Hanssen
Photo Credit: Federal Bureau of Investigation / Wikimedia Commons / Public Domain

Described as “possibly the worst intelligence disaster in US history,” the actions of traitor Robert Hanssen are the most recent on our list. He was an FBI agent from 1976-2001, and spent most of that time selling top-secret information to the Soviet Union and, following its collapse, to the Russians.

Hanssen leaked information about American spy equipment, such as radar and spy satellites, and revealed the names of agents spying on the Soviets. He also informed the USSR about a highly-secret eavesdropping tunnel built beneath the Soviet Embassy by the FBI.

On one occasion, Hanssen was tasked with identifying a mole within the FBI. Unbeknownst to his superiors, the individual was actually himself, which made it easy for him to cover his tracks. He remained anonymous throughout his career, and it was only on February 18, 2001, after a long investigation, that the FBI discovered he was a spy and arrested him.

On June 5, 2023, Hanssen, then 79, was found unresponsive in his prison cell at the ADX Florence supermax prison in Florence, Colorado. He was later pronounced dead, with an autopsy determining his passing was the result of colon cancer.

Fritz Duquesne

Fritz Duquesne looking to the side
Photo Credit: George Grantham Bain Collection / Library of Congress Prints and Photographs Division / Wikimedia Commons / Public Domain

Arguably the most unique military traitor on this list, Fritz Duquesne – better known as “The Duke” – was the leader of a German spy ring during the Second World War. A South African who’d fought for the Boers during the Second Boer War, he served as a secret agent for the Germans during both World Wars, conducting sabotage and gathering evidence in several Allied countries – in particular, the United States, the United Kingdom and South Africa. He was also active in South America.

During the First World War, Duquesne operated a spy ring that targeted British merchant vessels in South America. Prior to the US entering World War II, he operated a spy ring on American soil, made up of 33 German agents. Their covert activities were later revealed to the US government by a double agent.

Throughout his life, Duquesne operated under several aliases and was arrested on numerous occasions, managing to escape from the majority of the facilities he was sent to. He also served as an adviser for US President Theodore “Teddy” Roosevelt and found work in both the publishing and film industries.

Wang Jingwei

Wang Jingwei holding up his fist while talking
Photo Credit: CORBIS / Getty Images

The final entry on our list of the biggest military traitors in history is Wang Jingwei, a leftist politician in pre-Communist China who often clashed with his rival, Chiang Kai-shek.

At the beginning of World War II, Wang made a deal with Japan to hand over Nanjing, in return for him being given a puppet government that would be run in collaboration with the Japanese Empire. He frequently spoke about his admiration of Japan, with his speeches often reaffirming China’s submission to its neighbor. He died just before the end of the conflict.

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Once Japan was defeated by the Allies, Chiang’s government returned to Nanjing, where they destroyed Wang’s tomb and burned his body. All that remains of the site is a tiny pavilion that informs all who visit that he was a traitor.

Jesse Beckett

Jesse Beckett is one of the authors writing for WAR HISTORY ONLINE