War Plan Orange

War Plan Orange was the US Navy war plan for dealing with Japan. The general idea was that it would take a while to get going, and during that time the US would mobilize the Pacific Fleet (in peacetime, each ship had only half of its crew), defeat any vainglorious attack on the Panama Canal, and then sail for Hawaii and finally Manila. It was presumed that the Japanese would attack the Philippines but that they could hold out until the US fleet arrived from Hawaii. Once the fleet was in Manilla, it would sail due north and meet the Japanese battleships somewhere between the Philippines and Japan, defeat them, and then sail on to Japan. Once there, whether the United States invaded or not, the US fleet would blockade Japan.

Of course, the problem was the plan did not envision that aircraft could sink battleships, or that Japan would put the US battleship fleet out of action in an attack on Pearl Harbor. Many have questioned the move by Franklin Delano Roosevelt to send the fleet from California to Hawaii, since when war began it would have to be brought back to California to pick up the other half of the crews (consisting of mobilized reserves and new recruits).