The Aleutian Islands Campaign was a struggle over the Aleutian Islands, part of the Alaska Territory, in the American theater and the Pacific theater of World War II starting on 3 June 1942. A small Japanese force occupied the islands of Attu and Kiska, but the remoteness of the islands and the difficulties of weather and terrain meant that it took nearly a year for a far larger U.S./Canadian force to eject them. The islands' strategic value was their ability to control Pacific Great Circle routes. This control of the Pacific transportation routes is why U.S. General Billy Mitchell stated to the U.S. Congress in 1935, "I believe that in the future, whoever holds Alaska will hold the world. I think it is the most important strategic place in the world." The Japanese reasoned that control of the Aleutians would prevent a possible U.S. attack across the Northern Pacific. Similarly, the U.S. feared that the islands would be used as bases from which to launch aerial assaults against the West Coast.