Pearl Harbor advance-knowledge conspiracy theory

Various unproven conspiracy theories allege that U.S. government officials had advance knowledge of Japan's December 7, 1941, attack on Pearl Harbor. Ever since the Japanese attack, there has been debate as to why and how the United States was caught off guard, and how much and when American officials knew of Japanese plans for an attack.^[1][2] 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.^[3][4] Flynn was a political opponent of Roosevelt, and had strongly criticised 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.

Several writers, including journalist Robert Stinnett,^[5] retired U.S. Navy Rear Admiral Robert Alfred Theobald,^[6] and Harry Elmer Barnes^[7] have argued that various parties high in the government 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 theatre of World War II via a Japanese–American war started at "the back door", despite the fact Germany and Italy were not obliged to assist Japan in the event of aggression against another power.^[8][9][10] 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.^[11][12][13]