XXIX. THE LIKELIHOOD OF A JAPANESE ATTACK AT HAWAII AS ESTIMATED WASHINGTON DECEMBER 6, 1941

 

A. NAVY ESTIMATES

 

Admiral Stark testified that as of December 6, 1941, he considered that a United States and Japanese war was imminent and that there was a strong probability that Japan would strike. He thought that the Philippines and Guam were the most likely targets, of United States territory. He considered that an air attack on Pearl Harbor was possible but, he said, he thought that there was a good chance that any attack there would be detected in time to intercept it or to reduce its effectiveness (pages 73, 165) However, he had no information indicating that such an attack on Pearl Harbor was probable (pages 105 792). Generally speaking, he said, he and his advisors did not expect a raid on Hawaii (page 798).

 

Captain Wellborn said that there were various individuals in the Navy Department who felt that an attack on Pearl Harbor was probable‑such as Admiral Turner, and there were others who felt that it was less probable, although possible, such as Admirals Ingersoll and Stark.

 

Admiral Turner, on the other hand, testified that he had expected a landing in Southeast Asia, attacks on the Philippines and some form of attack on Hawaii

 

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(page 1002). He had thought that an aerial torpedo attack in Pearl Harbor was not only possible (page 997) but that it was a probability, and he was not surprised when it was made (page 1021).

 

Captain Glover said that a daily short strategic summary of the interna­tional military and political situation had been prepared by Commander Ansel in collaboration with Captain Wright and submitted to Admiral Turner. These are contained in a notebook entitled "Daily Information Summary-­Op 12" filed with the Combat Intelligence Section. Captain Glover said that he did not believe that it had generally been felt by officers in the Plans Division that the Japanese would strike as they did. (p. 176)

Admiral Turner said that he had always been of the view that a torpedo plane attack on ships in Pearl Harbor was possible and pointed out that the Bureau of Ordnance had modified its earlier letters indicating that still 75' depth was necessary.

Admiral Turner said that the Chief of Naval Operations shared his view as to the possibility of a surprise air attack on Pearl Harbor and that they felt that Admiral Kimmel also had the same views. (p. 261)

Admiral Turner said that generally he thought our Intelligence regarding Japanese intentions and activities was quite good. He said that he had anticipated that the Japanese would attack the United States, Great Britain and the Netherlands East Indies at the end of November 1941. The attack of December 7 came as no surprise to him whatsoever nor, he said, was it a surprise to the Chief of Naval Operations. He was not surprised by the Japanese attack upon Pearl Harbor and pointed out that he had originated the Secretary of the Navy's letter of January 1941, pointing out that just such an attack was the most probable form that the initiation of war by Japan would take. (p. 259)

Admiral Wilkinson recalled no specific evaluation as to the capability of the Japanese to launch an attack such as the attack which was made. (p. 287) Admiral Wilkinson said that he was not surprised by the fact that the Japanese did venture a carrier raid, but was surprised by the force of the raid, and by the fact that the attack had come in without detection. (p. 287‑8)

 

Admiral Ingersoll stated that he had considered that a surprise attack on Pearl Harbor was a possibility (page 821) but he had not thought that an air attack on Oahu was probable. He had thought that when war came there would be numerous Japanese submarines around Pearl Harbor and he expected raids against outlying islands in the Fourteenth Naval District and that any attack on Hawaii would be by submarines or surface forces (page 847). (3)

 

Admiral Ingersoll said that he thought the dispatches concerning the reenforcement of Midway and Wake should have accentuated the idea that there was a danger of raids in the area rather than allay suspicion as to the probability of attack in the Hawaiian area. (p. 427)

Admiral Ingersoll said that the December 3 dispatch indicated that war was imminent and a matter of a few days or hours and that it was believed in the office of the Chief of Naval Operations that such war would include the United States as indicated by the reference to Washington in that dispatch. (p.428)

Admiral Ingersoll said that he recalled no discussion in late November or early December regarding the probability of an air attack on Hawaii. They did anticipate possible attacks by submarines and possible raids either by light forces or by submarines at Wake, Midway and Johnston. (p. 426)

Admiral Ingersoll said that he expected that the Japanese attack against the United States would be on the Philippines and Guam with possible raiding attacks on our outlying islands to the westward of Hawaii and sub­marine attacks against shipping around Hawaii and generally between the west coast and the United States. He said that he did not recall anyone in operations reporting to Admiral Stark that the war would be precipitated by an air attack on Pearl Harbor. (p. 430)

 

Captain Heard testified that they had no information which indicated or would lead to an obvious conclusion that there was an impending attack on Hawaii. He was quite convinced that war would start in Southeast Asia (page 468).

 

Admiral Wilkinson said that for a month preceding 7 December 1941 there were no discussions in which he participated regarding the likelihood of a Jap­anese move on Pearl Harbor. He stated further that during the first week to

 

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December, 1941, he remembered no discussions concerning the question of whether or not aerial reconnaissance was being conducted from Oahu (p. 396).

 

According to Commander Kramer, from the information he saw there was not the slightest indication of Japanese overt intention to attack the United States. The information of this type was known to be incomplete and CNO knew this (page 985).

 

B. ARMY ESTIMATE

 

General Marshall said that he had felt that a Japanese attack would come in the Western Pacific, also possibly against the Panama Canal, which was then closed to the Japanese (page 861) The Japanese movements pointed to a move into Thailand, action to cut off the Burma Road, and a threat to the Malay‑Kra Peninsula, They had no indications of Japanese plans for assault on Hawaii (page 860-1). He always was in fear of a surprise attack on United States territory but the probabilities pointed to the Panama Canal and the Philippines before Hawaii; there were no specific indications in the possession of the Army and no reports from the Navy showing a threat against Hawaii (page 863). The attack on Pearl Harbor came as a surprise to General Marshall (page 882). It had appeared to him, as set forth in his letter in February 1941, that the pos­sibility in Hawaii in the way of attack was combined air and sabotage: There was a strong probability—really a certainty—that there was an evil intent in the Far East. The question was when it would explode and to what extent it would be on an infiltration basis. As to probability, Siam, the Malaya Peninsula, and the Panama Canal took priority, in his opinion, to Hawaii.

 

C. STATE DEPARTMENT ESTIMATES

 

Ambassador Grew said that he had received no report from the Korean under­ground that the Japanese would attack Pearl Harbor and Mr. Hamilton said that he had felt that the Japanese would move to the southward, but that he had not excluded from his estimates an attack on United States possessions (page 1075).