Fort Huachuca, AZ. – On the night of Dec. 6, 1941, a message to a Japanese delegation in Washington D.C. was intercepted, broken and distributed by the Signal Intelligence Service, or SIS.
This message, which would become known as the Fourteen Point Letter, clearly spelled out the Japanese claims that America was trespassing in the Far East. President Roosevelt, after reading the first 13 parts at 9:30 p.m., commented that this meant war. Officers in the SIS agreed, and felt sure that American Armed Forces would be on full alert.
The 14th part of the letter began to arrive at 5 a.m. on Dec. 7, 1941. It was deciphered by the Americans before the Japanese embassy. The letter declared in a single sentence that Japan was breaking off relations with the United States, and that the U.S. secretary of state should be notified at 1p.m. — dawn, in Hawaii. The president was informed immediately.
Gen. George Marshall, chief of staff of the Army, decided to alert the commanders of both the Hawaiian and Philippine department that the potential for attack was high. However, because of the sensitivity of the message, it was sent by telegraph. It wasn’t delivered to the ground commander in Hawaii until the Japanese bombers were flying through the morning fog over Pearl Harbor.