The Most Infamous Cases of Betrayal in US History

Spies and traitors operate in the shadowy world of subterfuge, expedience, and uncertain allegiances. We hear about spies when they are discovered plying their spycraft, such as Mata Hari during World War I, or traitors after they switch sides in war, like Norway’s infamous collaborator Vidkun Quisling in World War II. The United States has had its share of spies and traitors since the founding of the nation more than 250 years ago. (These are the most famous spies in history.) 

24/7 Tempo compiled a list of those responsible for the most notorious cases of betrayal in U.S. history in American history by consulting sources such as History Collection, Britannica, the FBI, and various Civil War websites. Confederate military figures were not included because they were granted clemency at the end of the Civil War, but the Confederacy’s politicians and sympathizers were not, and some of them appear here.  

Spies such as Rose Greenhow, a Washington, D.C., socialite, were part of a web of espionage agents who were working for the cause of the Confederacy. The Cold War and even the post-Cold War era revealed American spies operating in the employ of foreign powers, among them CIA agent Aldrich Ames and Taliban sympathizer John Anthony Walker Jr.

Traitors betray their country for a variety of reasons, including money (FBI agent Robert Hanssen), ideology (the Rosenbergs), and opportunism or revenge (Benedict Arnold). During World War II, turncoat Americans broadcasting propaganda in the service of Nazi Germany included Douglas Chandler, Robert Best, and Mildred Gillars, also known as “Axis Sally.” (Here’s a list of history’s most famous traitors.)

While those people willingly betrayed their country, Japanese-Americans Ikuko Toguri and Tomoya Kawakita were unwittingly stranded in Japan at the start of the war and coerced into working for the Japanese Empire as a broadcaster and an interpreter at a POW camp, respectively.