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.Pearl Harbor, Charles Sweeny, Arrow Press, Salt Lake City, UT, 1946.Pearl Harbor: The Seeds and Fruits of Infamy, Percy L. Greaves Jr., Ludwig von Mises Institute, 2010. Several writers, including journalist Robert Stinnett,Stinnet, Robert B. Day of Deceit: The Truth about FDR and Pearl Harbor (Touchstone paperback, 2001) retired U.S. Navy Rear Admiral Robert Alfred Theobald,Theobald, Robert A., Rear Admiral, USN (rtd). The Final Secret of Pearl Harbor – The Washington Contribution to the Japanese Attack (Devin-Adair Company, 1954). 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".Tansill, Charles C. Back Door to War: The Roosevelt Foreign Policy, 1933–1941 (Henry Regnery Company, 1952).Sanborn, Frederic R. Design For War: A Study of Secret Power Politics 1937–1941 (Devin-Adair Company, 1951).
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 (1941); the Roberts Commission (1941–42); the Hart Inquiry (1944); the Army Pearl Harbor Board (1944); the Naval Court of Inquiry (1944); the Hewitt investigation; the Clarke investigation; the Congressional InquiryIn general, "Congressional inquiry" refers to any United States congressional hearing. (Pearl Harbor Committee; 1945–46); a top-secret inquiry by Secretary of War Henry L. Stimson, authorized by Congress and carried out by Henry Clausen (the Clausen Inquiry; 1946); and the Thurmond-Spence hearing, in April 1995, which produced the Dorn Report. (Source: Office of the Under Secretary of Defense for Personnel and Readiness. Online page created December 24, 1996, begun by Larry W. Jewell.) 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 consultation between them); and lack of adequate manpower for intelligence (analysis, collection, processing).Holmes, Double-Edged Secrets; Prange et al, Pearl Harbor: The Verdict of History
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.Pearl Harbor: Final Judgement, Henry C. Clausen and Bruce Lee, HarperCollins, 2001, p. 269. Clausen claimed, in spite of Secretary Stimson having given him a letter informing witnesses he had the necessary clearances to require their cooperation, that 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, Review of Henry C. Clausen and Bruce Lee, Pearl Harbor: Final Judgment (New York: Crown Books, 1992). 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.Wohlstetter, Pearl Harbor – Warning and Decision, p. 35.
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.Costello, John. The Pacific War 1941–1945. p. 627f, reprinted by Taylor & Francis in 2017 with , republished in
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 Secretary of the Navy Frank Knox and was very close to President Franklin D. Roosevelt's inner circle. He remarked that:
Another "eyewitness viewpoint" akin to Beatty's is provided by Roosevelt's administrative assistant at the time of Pearl Harbor, Jonathan W. 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. ..."1941: Pearl Harbor Sunday: The End of an Era, in "The Aspirin Age – 1919–1941," edited by Isabel Leighton, Simon and Schuster, New York, 1949, page 490.
"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 [the Japanese] into the position of firing the first shot without allowing too much danger to ourselves.'"Cumings, Bruce: "Parallax Visions: Making Sense of American-East Asian Relations" Duke 1999 p. 47; Text above from Wikipedia's Henry L. Stimson 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:[Yet] 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. ...quoted in
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 (or Congress) 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.Young, p. 2. 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" (actions to be taken) 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.Notes for Chapter Two, paperback edition, pp. 321–322, notes 7, 8, and 11. 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, "[t]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."Parillo, Mark, "The United States in the Pacific", in Higham, Robin, and Harris, Stephen, Why Air Forces Fail: The Anatomy of Defeat (Lexington: University Press of Kentucky, 2006), p. 289. 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...."Prange, Gordon W., Dillon, Katherine V., and Goldstein, Donald M. At Dawn We Slept: The Untold Story of Pearl Harbor (New York: Penguin, 1991), p. 336. Additionally, in a November 21, 1941, memo, Brigadier Leonard T. Gerow, head of Army War Plans, stated, "one of our present major objectives [is] the avoidance of war with Japan...[and to] insure continuance of material assistance to the British."Prange, et al., At Dawn We Slept: The Untold Story of Pearl Harbor (New York: Penguin, 1991), p. 369. He concluded, "[I]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 an October 4 message requesting a USN courtesy visit to Singapore, then a British colony, aimed at "preventing the spreading of the war"Prange et al., At Dawn We Slept, p. 861. 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..."Prange et al., At Dawn We Slept, quoted p. 861. 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.