During the closing weeks of the Pacific war, Lieutenant Lea Booth and the rest of Admiral William Halsey’s dirty Tricks Department faced a daunting task: fool the enemy into thinking an invasion of southern Japan was under way.

By Master Chief Communications Technician
Thomas H. Helvig, U.S. Navy (Retired)

Although many books and articles have been written about radio deception used during World War II, a top-secret hoax carried out on the USS Tucson (CL 98) remained an untold story for more than 60 years.  An to this day, very few Tucson crewmen know the real reason their ship suddenly came about and pulled away from Task Force 38 (TF 38) in the early afternoon of 10 July 1945.  In fact, the light cruiser was the centerpiece of a complex operation planned by Rear Admiral Robert B. Carney, the Third Fleet’s chief of staff.  The Sailors on board her who would pull the wool over Japanese eyes (and ears) were member of Admiral William F. Halsey’s “Dirty Tricks Department,” led by Lieutenant A. Lea Booth, U.S. Naval Reserve.

Building Up to the Ruse

A native of Danville, Virginia, Booth had graduated from the Old Dominion’s Washington and Lee University in 1940 before moving to the nation’s capital and getting a job with the Department of Agriculture.  “A buddy and I stood inside the Capital building and President Roosevelt gave his speech to the nation on December 8, 1941, and Congress declared war,” Booth recalled.  “A few hours later, we both stood naked at the Washington Navy Yard waiting for our physicals.”  After surviving boot camp, receiving a commission, and attending Navy Communications School in Washington, Both shipped out for the Pacific in December 1942.  He ended up in Noumea, New Caledonia, assigned to Communications Security (COMSEC) Unit #41, a small section of Admiral Halsey’s South Pacific Force staff, and through the end of the war his primary assignment would remain with the unit.

The section’s initial duty was to monitor U.S. Navy frequencies for communications violations that might compromise U.S. codes and ciphers.  Unit #41 moved to Munda Point, New Georgia, after its capture by U.S. force in August 1943, and Booth was later assigned to monitor radio traffic on the beachhead at Bougainville.  When the commanding officer of the advanced based there, Captain Oliver O ”Scrappy” Kessing, traced a reprimand from Halsey’s headquarters back to the lieutenant, Booth was given 24 hours to get off the island or face a court-martial.  He later dryly noted, “The receipt of a communications improvement memorandum was not very popular with commanding officers in the South Pacific.”  Booth returned to Noumea, but Admiral Carney defended his actions and chastised Kessing.  The lieutenant next received a temporary additional duty assignment in Washington.  There, he help manipulate the radio traffic flow between the capital and Allied headquarters outside London so German intelligence would not be able to determine the planned date of the 6 June 1944 D-Day landing by analyzing the expected pre-invasion increase of transmissions

On 7 June, Lieutenant Booth was on his way back to the Pacific where he next set up and ran a radio intercept operation from the Dole pineapple fields on Oahu.  He reported his results directly to Admiral Carney.  Booth recalled that his team monitored “U.S. Pacific Fleet radio circuits to determine if U.S. Fleet movements and future Fleet operations could be predicted through the study of traffic analysis and direction finding.”  According to Carney, the snoopers “learned that the Japanese … could deduce real information just by analyzing the nature and volume of radio traffic.”  Moreover, U.S. cryptanalysts who had broken the Japanese codes determined that the enemy was in fact doing exactly that.

After Admiral Carney read Booth’s surprisingly accurate reports predicting U.S. ship movements, he directed COMSEC staffers to explore how Japanese knowledge of the radio traffic patterns could be used against the enemy.  Orders were soon issued for members of Unit #41 – Lea Booth, Lieutenant (junior grade), Leslie Wright, and half a dozen rated radiomen – form a Dirty Tricks Department attached to Halsey’s Third Fleet staff.  According to Booth, “We were being assigned for deceptive missions at sea and to mislead Japanese intelligence as to the actual target destinations of Task Force 38.”