In the mid-1930s, just as the United States was embarking on a policy of neutrality, Nazi Germany embarked on a program of espionage against the unwary nation. Hitler’s attempts to interfere in American affairs by spreading anti-Semitic propaganda, stealing military technology, and mapping US defenses.

Today’s guest is Rhodri Jeffreys-Jones, author of the book “The Nazi Spy Ring in America.” Using recently declassified material, he shows how Germany’s foreign intelligence service, the Abwehr, was able to steal top secret US technology such as a prototype codebreaking machine and data about the latest fighter planes.

Enlisting the services of German-American fascists and anti-Semites, they resorted to ruthless methods to achieve their goals, including murdering the wife and daughter of an American industrialist. When the spy ring was busted in 1938 by FBI agent Leon Turrou, the ensuing trial caused a national sensation and played a significant role in shifting public opinion against Germany, awakening many Americans to the looming Nazi threat.

This story provides essential insight into the role of espionage in shaping American perceptions of Germany in the years leading up to US entry into World War II and sheds light on a now-forgotten but significant episode in the history of international relations.