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 .
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 concealment. Two airplane transports would be provided, each loaded with fifty bombardment planes. These ships could be equipped with a flying-off deck laid down in sections while the transports were in use. These seacraft would be started so as to arrive at the islands of Niihau [the smallest and westernmost of the Hawaiian Islands, it is now privately owned and operated as a sheep ranch—Ed.] and Midway respectively on “D” day.
3. The submarines with the pursuit equipment aboard would land at Niihau on the evening of “D” day and, as there are only 140 people on the island, no radio station or other means of communication, except by water, probably the first information of this force, received at Honolulu, would be the appearance of the hostile aircraft.…
4. The pursuit ships could be set up and made ready for service during the night and be ready for duty the next morning. (Twenty submarines could carry twice as many pursuit ships as the ten mentioned above.) The force destined for Midway Island could debark its bombardment equipment from the transports, prepare the airdrome in the sand with landing mats and the necessary auxiliaries to the aircraft. All the islands between Midway and Niihau would be occupied with observation posts and radio sets.
5. The flying time between Midway to Niihau is eleven hours. By equipping the bombers with auxiliary gas tanks in their bomb compartments a cruising ability of about sixteen hours can easily be given them. As soon as set up and tested, those ships would fly to Niihau and be ready to attack Oahu immediately afterwards. While these operations are taking place the Island of Guam would be seized. (Under these conditions the Philippines would fall of their own weight within a year or two.)
6. The distance from Niihau to Honolulu is about 150 miles, or an hour and a half flight, or a total of three hours there and back; allowing forty minutes for an attack and an additional twenty minutes for eventualities would require a maximum of four hours for one attack mission. (The present United States pursuit airplane with auxiliary gas tank has four and a half hours’ fuel; the bomber, about six.)
7. The first attack would be arranged as follows: Japanese pursuit, sixty ships, organized into one group of three squadrons of twenty ships each; two squadrons to participate in combined attack with bombardment and one squadron to remain in reserve on the alert.…The objectives for attack are: (1) Ford Island airdrome hangars, storehouses, and ammunition dumps (2) Navy fuel oil tanks (3) Water supply of Honolulu (4) Water supply of Schofield (5) Schofield Barracks airdrome and troop establishments (6) Naval submarine station (7) City and wharves of Honolulu
8. Attack will be launched as follows: Bombardment
Attack to be made on Ford’s Island at 7:30 A.M.…