The McCollum Memo
To some conspiracy theorists, the McCollum Memo is the smoking gun which proved that FDR and the American military were aware in advance of the impending Japanese attack on Pearl Harbor, having deliberately provoked the Japanese into action. This presupposes that Roosevelt wanted a war in the Pacific and Europe at the same time. Roosevelt was a consummate politician well aware that the Tripartite Pact meant that Hitler had an obligation to declare war on the United States if the US attacked Japan, but he was under no obligation to do so if the Japanese attacked first.
The content of the McCollum Memo recommends steps for the United States to strengthen its position in the Pacific in a manner which could prevent further Japanese aggression. It specifically recommends that the United States keep the Pacific Fleet in Hawaii, where it was better positioned to respond to any Japanese move. It also suggested strengthening the Asiatic fleet, and ensuring sufficient arrangements were made with the Dutch and British for mutual use of bases. It was written in the fall of 1940, and was read and approved by multiple senior officers, (its author was a Lieutenant Commander) who later denied that its intent was to push the Japanese into attacking the Americans or their allies.
Throughout the 1920s and 1930s America’s strategy for prosecuting a war against Japan was developed as Plan Orange. Essentially American military planners believed that an attack on the US would likely be directed at the Philippines and some of the territorial islands, including the Aleutians. It did not anticipate an attack on the fleet at Pearl Harbor, or even the fleet being positioned at Pearl Harbor, instead the fleet would muster its crews and sojourn from its normal west coast bases. While the plan evolved as a result of annual training exercises it did not vary greatly from the original.
With the Philippines likely to be attacked the strengthening of the Asiatic fleet, and the positioning of the main battle fleet at Hawaii, was a precaution ensuring the Philippines of an adequate defense while the battle fleet sortied to their aid. Fleet problems and training exercises had made the need to do so apparent. The Japanese did attack the Philippines about eight hours after the attack on Pearl Harbor. They achieved almost total surprise. The air power stationed there was mostly destroyed on the ground. Still American and Filipino troops managed to hold out on Bataan for nearly four months, but there was no fleet to come to their support.
The McCollum Memo and the American leadership did not anticipate the scope of the initial Japanese actions in December 1941, nor the quality of its pilots and aircraft. American generals and admirals in the aftermath of the initial attacks were soon pointing the finger of blame at each other and at Washington. When Roosevelt requested a declaration of war from Congress there was no mention of Germany or Italy. Roosevelt wanted a war with Germany and recognized the possibility, even the probability, that the US would be fighting all three of the Axis nations. But allowing an attack on Pearl Harbor did not guarantee a war with Germany. It took Adolf Hitler to do that.