The A to Z Challenge asks bloggers to post 26 posts, one for each letter of the English alphabet, in April. Most of us choose to make these posts on a particular theme. My theme for 2022 is Codebreaking in World War II, which fits with the topic of the novel that I’m writing. Visit every day (except Sunday) in April for a new post on my topic.

H is for J. Edgar Hoover

In 1941, the FBI successfully uncovered Nazi spies in New York, with the help of Elizebeth Friedman and her team at the coast guard.

“The coast guard’s patient codebreaking, combined with the FBI’s surveillance footage and the cooperation of the double agent William Sebold, led to what J. Edgar Hoover called “the greatest spy round” in U.S. history, a series of raids in June 1941 conducted by ninety-three FBI agents and sweeping up Duquesne and thirty-two members of his ring…. After six weeks of sensational testimony by FBI agents and Duquesne himself, all defendants were convicted, and the thirty-three spies were sentenced to three hundred years collectively.” (p. 233-4, The Woman Who Smashed Codes by Jason Fagone)

Hoover in 1940

The case made J. Edgar Hoover a legend.

Elizebeth Friedman, however, was less impressed. She thought that the FBI exposed too many secrets of the cryptography craft, all in the cause of publicity-seeking.

Her concerns proved to be well-founded. A year later, the FBI orchestrated a round-up of Nazi spies in Brazil in order to break up a ring that, among other things, tracked the movement of Allied ships to be targeted by U-boats.

“The FBI’s plan didn’t work. The roundup failed. To deliver a deathblow to the Nazi network, to keep the spies off the airwaves, the FBI needed to get all the spies at once. But they didn’t.” (p. 247)

Before the roundup, Elizebeth Friedman and her team had broken the code that the spy ring was using and were successfully reading their messages. As Joseph Wenger, head of the Navy’s cryptanalysis unit, wrote in an internal memo, “It might be much more valuable to the military services to obtain the information flowing through clandestine stations than to close them up.” (p. 254)

But it was too late.

“Elizebeth, Lieutenant Jones, and their coast guard teammates watched in frustration as new circuits lit up throughout the summer and fall of 1942—two, then five, then fifteen—each using a different and yet-unbroken code. It was as if the FBI had tried to destroy an approaching asteroid with a single huge bomb but instead just blasted the rock into dozens of sentient fragments able to regenerate and spread wreckage over a wider swath of earth.” (p. 253)

For the duration of the war, the intelligence agencies in both the US and Britain distrusted the FBI and left them out of the loop as much as possible.

That didn’t keep J. Edgar Hoover from taking credit for smashing Nazi spy rings in South America. While other federal employees were silenced by their secrecy oaths, Hoover didn’t have to worry. “His power allowed him to manipulate the press and disclose secrets without consequence.” (p. 299) In the fall of 1944, he wrote a seven-page article in The American Magazine and starred in a fifteen-minute documentary spinning the FBI’s work in South America during World War II as entirely helpful to the war effort and not giving credit to any of the other agencies or the people worked in them.

For more information on this fascinating story, check out The Woman Who Smashed Codes by Jason Fagone.