Tanks of the United States saw limited action in the battle for Normandy as armored recovery vehicles with dummy guns. The M4 was the best known and most used American tank of World War II. Christened "Sherman" by the British, it was named for the famous US Civil War General, William Tecumseh Sherman. The M4 Sherman was a medium tank that proved itself in the Allied operations in North Africa, Europe and the Pacific theaters of war in World War II. The Sherman was a relatively inexpensive, easy to maintain and produce combat system. Similar to production efforts on the part of the Soviet Union
US signals intelligence in the Cold War continuing the World War II legacy. President Harry Truman, on 24 October 1952, issued a directive that set the stage for the National Security Agency, whose scope went beyond the pure military. NSA was created on 4 November 1952. Air Force SIGINT, by the Air Force Security Service, supported numerous Korean War operations. They often gave early warning of bombing attacks or ambushes for fighter aircraft. Since the North Koreans operated under Soviet doctrine, with strict ground control, the ground-controlled interception communications were especially vulnerable. North Korean orders to bombing units might well be intercepted and processed in the US