European theatre of World War II
Several writers, including journalist Robert Stinnett, retired U.S. Navy Rear Admiral Robert Alfred Theobald, and Harry Elmer Barnes have argued 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". However, the Pearl Harbor advance-knowledge conspiracy is rejected by most historians as a fringe theory.