Pearl Harbor advance-knowledge conspiracy theory
The Pearl Harbor advance-knowledge conspiracy theory is an unproven conspiracy theory alleging that U.S. government officials had advance knowledge of Japan's 1941 attack on Pearl Harbor.
Starting from shortly after the attack, there has been debate as to what extent the United States was caught off guard, and how much and when American officials knew of Japanese plans for an attack. Several writers, including journalist Robert Stinnett, retired U.S. Navy Rear Admiral Robert Alfred Theobald, and Harry Elmer Barnes, have argued that various parties high in the governments of the United States and the United Kingdom knew of the attack in advance and may even have let it happen or encouraged it in order to ensure America’s entry into the European theater of World War II via a Japanese–American war started at "the back door".
The Pearl Harbor advance-knowledge conspiracy theory is rejected by most historians as a fringe theory, citing several key discrepancies and reliance on dubious sources.
Ten official U.S. inquiries
In September 1944, John T. Flynn, a co-founder of the non-interventionist America First Committee, launched a Pearl Harbor counter-narrative when he published a 46-page booklet entitled The Truth about Pearl Harbor, arguing that Roosevelt and his inner circle had been plotting to provoke the Japanese into an attack on the U.S. and thus provide a reason to enter the war since January 1941. Flynn was a political opponent of Roosevelt, and had strongly criticized him for both his domestic and foreign policies. In 1944, a congressional investigation conducted by both major political parties provided little by way of vindication for his assertions, despite Flynn being chief investigator.The U.S. government made nine official inquiries into the attack between 1941 and 1946, and a tenth in 1995. They included an inquiry by Secretary of the Navy Frank Knox ; the Roberts Commission ; the Hart Inquiry ; the Army Pearl Harbor Board ; the Naval Court of Inquiry ; the Hewitt investigation; the Clarke investigation; the Congressional Inquiry ; a top-secret inquiry by Secretary of War Henry L. Stimson, authorized by Congress and carried out by Henry Clausen ; and the Thurmond-Spence hearing, in April 1995, which produced the Dorn Report. The inquiries reported incompetence, underestimation, and misapprehension of Japanese capabilities and intentions; problems resulting from excessive secrecy about cryptography; division of responsibility between Army and Navy ; and lack of adequate manpower for intelligence.
Investigators prior to Clausen did not have the security clearance necessary to receive the most sensitive information, as Brigadier General Henry D. Russell had been appointed guardian of the pre-war decrypts, and he alone held the combination to the storage safe. Clausen claimed, in spite of Secretary Stimson having given him a letter informing witnesses he had the necessary clearances to require their cooperation, he was repeatedly lied to until he produced copies of top secret decrypts, thus proving he indeed had the proper clearance.
Stimson's report to Congress, based on Clausen's work, was limited due to secrecy concerns, largely about cryptography. A more complete account was not made publicly available until the mid-1980s, and not published until 1992 as Pearl Harbor: Final Judgement. Reaction to the 1992 publication has varied. Some regard it as a valuable addition to understanding the events, while one historian noted Clausen did not speak to General Walter Short, Army commander at Pearl Harbor during the attack, and called Clausen's investigation "notoriously unreliable" in several respects.
Diplomatic situation
Some authors argue that President Roosevelt was actively provoking Japan in the weeks prior to the Pearl Harbor attack. These authors assert that Roosevelt was imminently expecting and seeking war, but wanted Japan to take the first overtly aggressive action.Statements by high-ranking officials
One perspective is given by Rear Admiral Frank Edmund Beatty Jr., who at the time of the Pearl Harbor attack was an aide to the Secretary of the Navy Frank Knox and was very close to President Franklin D. Roosevelt's inner circle, remarked that:Another "eyewitness viewpoint" akin to Beatty's is provided by Roosevelt's administrative assistant at the time of Pearl Harbor, Jonathan Daniels; it was a comment about FDR's reaction to the attack – "The blow was heavier than he had hoped it would necessarily be.... But the risks paid off; even the loss was worth the price...."
"Ten days before the attack on Pearl Harbor", Henry L. Stimson, United States Secretary of War at the time, "entered in his diary the famous and much-argued statement – that he had met with President Roosevelt to discuss the evidence of impending hostilities with Japan, and the question was 'how we should maneuver them into the position of firing the first shot without allowing too much danger to ourselves.'" However Stimson, in reviewing his diary after the war, recalled that the commanders at Pearl Harbor had been warned of the possibility of attack, and that the poor state of readiness that the attack had revealed was a surprise to him:
General Short had been told the two essential facts: 1) a war with Japan is threatening, 2) hostile action by Japan is possible at any moment. Given these two facts, both of which were stated without equivocation in the message of Nov. 27, the outpost commander should be on the alert to make his fight ...
To cluster his airplanes in such groups and positions that in an emergency they could not take the air for several hours, and to keep his antiaircraft ammunition so stored that it could not be promptly and immediately available, and to use his best reconnaissance system, radar, only for a very small fraction of the day and night, in my opinion betrayed a misconception of his real duty which was almost beyond belief. ...
Robert Stinnett's Day of Deceit suggests a memorandum prepared by Commander McCollum was central to U.S. policy in the immediate pre-war period. Stinnett claims the memo suggests only a direct attack on U.S. interests would sway the American public to favor direct involvement in the European war, specifically in support of the British. An attack by Japan would not, could not, aid Britain. Although the memo was passed to Captains Walter Anderson and Dudley Knox, two of Roosevelt's military advisors, on October 7, 1940, there is no evidence to suggest Roosevelt ever saw it, while Stinnett's claims of evidence he did is nonexistent. Moreover, although Anderson and Knox offered eight specific plans to aggrieve the Japanese Empire and added, "If by these means Japan could be led to commit an overt act of war, so much the better," of the eight "plans" offered in the memo, many if not all were implemented, but there is considerable doubt the McCollum memo was the inspiration. Nonetheless, in Day of Deceit Stinnett claims all action items were implemented. Yet there were numerous instances of members of the Roosevelt Administration insisting on not provoking Japan. Mark Parillo, in his essay The United States in the Pacific, wrote, "hese theories tend to founder on the logic of the situation. Had Roosevelt and other members of his administration known of the attack in advance, they would have been foolish to sacrifice one of the major instruments needed to win the war just to get the United States into it." Furthermore, on November 5, 1941, in a joint memo, Stark, CNO, and Marshall, Army Chief of Staff, warned, "if Japan be defeated and Germany remain undefeated, decision will still not have been reached.... War between the United States and Japan should be avoided...." Additionally, in a November 21, 1941, memo, Brigadier Leonard T. Gerow, head of Army War Plans, stated, "one of our present major objectives the avoidance of war with Japan... insure continuance of material assistance to the British." He concluded, "t is of grave importance to our war effort in Europe..." Furthermore, Churchill himself, in a May 15, 1940, telegram, said he hoped a U.S. commitment to aid Britain would "quiet" Japan, following with a October 4 message requesting a USN courtesy visit to Singapore aimed at "preventing the spreading of the war" And Stark's own Plan Dog expressly stated, "Any strength that we might send to the Far East would...reduce the force of our blows against Germany..." Roosevelt could scarcely have been ignorant of Stark's views, and war with Japan was clearly contrary to Roosevelt's express wish to aid Britain.
Oliver Lyttelton, the British Minister of War Production, said, "... Japan was provoked into attacking the Americans at Pearl Harbor. It is a travesty of history ever to say that America was forced into the war. Everyone knows where American sympathies were. It is incorrect to say that America was truly neutral even before America came into the war on an all-out basis." How this demonstrates anything with regard to Japan is unclear. Rather, it refers to other aid to Britain. Lend-Lease, enacted in March 1941, informally declared the end of American neutrality in favor of the Allies by agreeing to supply Allied nations with war materials. In addition, Roosevelt authorized a so-called Neutrality Patrol, which would protect the merchantmen of one nation, namely Britain, from attack by another, Germany. This made shipping legitimate target of attack by submarine. Furthermore, Roosevelt ordered U.S. destroyers to report U-boats, then later authorized them to "shoot on sight". This made the U.S. a de facto belligerent. None was the act of a disinterested neutral, while all are unquestionably of assistance to Britain.
When considering information like this as a point for or against, the reader must keep in mind questions such as: was this official privy to information about the U.S. government? Did he have communications with high-level administration figures such as President Roosevelt or Ambassador Joseph Grew? Is this just a strongly held personal opinion? Or were there measures justifying this view? If Britain, did, indeed know and chose to conceal, "withholding this vital intelligence only ran the risk of losing American trust", and with it any further American aid, which would be reduced after the attack in any event.
There is also a claim, first asserted in John Toland's Infamy, that ONI knew about Japanese carrier movements. Toland cited entries from the diary of Rear Admiral J. E. Meijer Ranneft of the Dutch Navy for December 2 and 6. Ranneft attended briefings at ONI on these dates. According to Toland, Ranneft wrote that he was told by ONI that two Japanese carriers were northwest of Honolulu. However, the diary uses the Dutch abbreviation beW, meaning "westerly", contradicting Toland's claim. Nor did any other persons present at the briefings report hearing Toland's version. In their reviews of Infamy, David Kahn and John C. Zimmerman suggested Ranneft's reference was to carriers near the Marshall Islands. Toland has made other conflicting and incorrect claims about the diary during lectures at the Holocaust denial organization the Institute for Historical Review.
The diary states at 02:00 Turner fears a sudden Japanese attack on Manila. At 14:00 the diary states "Everyone present on O.N.I. I speak to Director Admiral Wilkinson, Captain MacCollum, Lt. Cdr. Kramer ... They show me – on my request – the place of the 2 carriers West of Honolulu. I ask what the idea is of these carriers on that place. The answer was: 'perhaps in connection with Japanese rapports on eventual American actions'. There is not one of ours who speaks about a possible air attack on Honolulu. I myself did not think of it because I believed everyone on Honolulu to be 100% on the alert, as everyone here on O.N.I. There prevails a tense state of mind at O.N.I." These diary entries are provided in the photo section in George Victor's The Pearl Harbor Myth: Rethinking the Unthinkable.
CBS correspondent Edward R. Murrow had a dinner appointment at the White House on December 7. Because of the attack he and his wife only ate with Mrs. Roosevelt, but the president asked Murrow to stay afterwards. As he waited outside the Oval Office, Murrow observed government and military officials entering and leaving. He wrote after the war:
One historian has written, however, that when Murrow met Roosevelt with William J. Donovan of the OSS that night, while the magnitude of the destruction at Pearl Harbor horrified the president, Roosevelt seemed slightly less surprised by the attack than the other men. According to Murrow, the president told him, "Maybe you think didn't surprise us!" He said later, "I believed him", and thought that he might have been asked to stay as a witness. When allegations of Roosevelt's foreknowledge appeared after the war, John Gunther asked Murrow about the meeting. Murrow reportedly responded the full story would pay for his son's college education and "if you think I'm going to give it to you, you're out of your mind". Murrow did not write the story, however, before his death.
British-Australian author Jesse Fink asserts in his 2023 biography of MI6 intelligence officer Dick Ellis that Roosevelt knew an attack would be forthcoming. Ellis helped William Donovan set up the Office of Strategic Services and was deputy to William Stephenson at British Security Co-ordination.
In Fink's book, The Eagle in the Mirror, Ellis is quoted as saying: ‘ was convinced from the information that was reaching him that this attack was imminent, and through Jimmy Roosevelt, President Roosevelt’s son, he passed this information to the President. Now whether the President at that time had other information which corroborated this... it’s impossible to say.'