When The Japanese Failed To Notice The Navy Had Cracked Their Code

Photo Credit: 1. US Navy / Wikimedia Commons 2. Cdr. John Ford, USNR / Wikimedia Commons

The Battle of Midway was an integral part of America’s war in the Pacific Ocean. The battle resulted in extensive damage to the Japanese fleet, but what many may not be aware of is that it was also the scene of one of WWII’s biggest security breaches… Well, it would have been if everyone had been a touch more observant.

The Battle of the Coral Sea

The story starts with the Battle of the Coral Sea in May 1942, a month before the Battle of Midway. Australian-American reporter Stanley Johnston was aboard the USS Lexington, which was run by Admiral Chester W. Nimitz. Johnston, who worked for the Chicago Tribune, was the only journalist aboard the aircraft carrier and had been vetted by the FBI before boarding.

During the battle, the USS Lexington was sunk by enemy forces. While evacuations were happening, Johnston ran below deck to rescue soldiers who’d been badly burned and helped transfer them onto the USS Barnett. From there, he and the other survivors began their voyage to San Diego, California via Nouméa.

Japanese aircraft carrier under attack during the Battle of the Coral Sea
Japanese aircraft carrier under attack during the Battle of the Coral Sea. (Photo Credit: National Museum of the U.S. Navy / Wikimedia Commons)

While aboard the USS Barnett, Johnston roomed with Commander Morton Seligman, executive officer of the sunken USS Lexington. Seligman was privy to Navy intel and received a top-secret message from Admiral Nimitz, no. 311221. While it’s unknown whether the Commander told Johnston or if the reporter came upon the note, its contents were soon be published for all of America to read.

Implied, but not explicitly stated

Johnston published 15 first-hand accounts from the battle with the Tribune. He also published a story on the American victory at Midway, with the title, “Navy Had Word of [Japanese] Plan to Strike at Sea.” It was a story so big that it was picked up by the San Francisco Chronicle and published on its front page.

While the story did not explicitly state the Japanese code had been broken by the U.S. Navy, it did strongly imply that was the case. It explained that Navy officials had advance knowledge regarding the attack at Midway, along with the size and schedule of the Imperial Japanese Navy’s armada.

Screenshot of the Chicago Tribune headline from the Sunday edition
Photo Credit: The Editorial Board / Chicago Tribune

The leak caused an uproar within the Navy and the federal government. President Franklin D. Roosevelt was incredibly upset with the journalist, who was aware that such stories required the approval of Washington. While many agreed Naval personnel should have been more discreet with sensitive information, it was policy for reports written from war zones to be sent to the Naval Censorship Office before publication.

Hearing before a grand jury

Due to the potential security breach such an article could pose, the FBI, the Navy, and the Justice Department petitioned U.S. Attorney General Francis Biddle to charge Johnston and Tribune managing editor Patrick Maloney under the Espionage Act of 1917. The move would be the first and only time the act was used against a journalist.

The first four days of the trial featured witness testimony, with the fifth scheduled to feature Navy brass. The aim was to show the members of the jury how Johnston’s story could negatively affect the country’s war efforts. However, Ernest King, Chief of Naval Operations, denied the opportunity for his officers to testify. This severely hindered Biddle’s case, as the grand jury found it difficult to indict the men on charges they didn’t fully understand.

Headshot of Stanley Johnston
Stanley Johnston. (Photo Credit: Jcdurand3391 / Wikimedia Commons CC BY-SA 4.0)

Johnston and Maloney were acquitted by the grand jury of all charges, due to a lack of testimony on behalf of the Navy and because the Espionage Act didn’t cover enemy secrets. This ended up being a blessing in disguise for the Navy, as it meant the matter would soon be forgotten by the American public, lessening the chances of the Japanese learning about the breach.

Anger and aftermath

While the grand jury trial was underway, other proposals were discussed regarding possible ramifications against the newspaper. It was suggested the Navy requisition the ships used to bring newsprint across the Great Lakes, while another proposed the suspension of pulp deliveries to Robert R. McCormick, owner of the Tribune. Neither came to fruition.

Luckily for the Navy, the Japanese never learned that they’d deciphered their code. While their military updated its code every few months, they never altered their basic code (JN-25) and never changed it to the point of making it indecipherable.

Planes and crewmen aboard the USS Enterprise during the Battle of Midway
U.S. Navy Torpedo Squadron 6 on the USS Enterprise during the Battle of Midway. (Photo Credit: Unknown Author / Wikimedia Commons)

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Commander Seligman was punished for his involvement in the leak. He was transferred to shore duty by Admiral King and was never promoted to captain. The damage to his career was such that he was forcibly retired from Naval duties in 1944.