In the fall of 1923, Brigadier General William “Billy” Mitchell, then Assistant Chief of the young Army Air Service, was sent on an inspection tour of the Pacific. Upon his return, Mitchell publicly voiced opinions about the inadequacies of our Pacific defenses and the very real threat of Japanese aggression that caused a furor in the War Department.

Among other things Mitchell warned that the Hawaiian Islands—and, in particular, the great naval base at Pearl Harbor—were open to a Japanese surprise air attack. He then proceeded to outline how such an attack could be made successfully. Because Mitchell failed to reckon on the development of the aircraft carrier, many details of his plan now seem unnecessarily elaborate, if not fantastic; but in the light of what happened on December 7, 1941, his total concept proved alarmingly accurate.

The prophetic words which appear below are published for the first time. They are taken from the original report that Mitchell wrote in 1924—a 525-page manuscript recently brought to light after years of obscurity in the classified files of the War Department and the National Archives .

—Ed.

I. The Military Importance of the Island of Oahu

1. Assuming a state of war to be impending and with the mission of the Hawaiian Department to be the holding of the Island of Oahu for four months before the arrival of supporting troops, let us estimate what the action of Japan will be.…She knows full well that the United States will probably enter the next war with the methods and weapons of the former war, and will, therefore, offer the enticing morsel which all nations that have followed this system have done before. Japan also knows full well that the defense of the Hawaiian Group is based on the defense of the Island of Oahu and not on the defense of the whole group.

2. The Island of Oahu, with its military depots, both naval and land, its airdromes, water supplies, the city of Honolulu with its wharves and supply points, forms an easy, compact and convenient object for air attack.…

II. Possible Plan of Attack of the Hawaiian Islands and Results Thereof.

1. There is no adequate defense against air attack except an air force. This can be supplemented by auxiliaries on the ground, such as cannon, machine guns, and balloon barrages, but without air power these arrangements act only to give a false sense of security, such as the ostrich must feel when he hides his head in the sand.…

2. I believe, therefore, that should Japan decide upon the reduction and seizure of the Hawaiian Islands, the following procedure would be adopted. Ten submarines would be loaded with six pursuit airplanes and spares each, the airplane crates being made in two segments so that each one could be used as a barge when emptied of its cargo. These crates would be carried as deck loads, the boats would dive only for