FDR Knew of the Pearl Harbor Attack in Advance
One of the more pernicious myths, which first surfaced during the 1944 presidential campaign, claims that FDR knew in advance of the Japanese plan to attack Pearl Harbor, but allowed it to happen in order to bring the US into the war on Britain’s side against Germany. Aside from the absence of any evidence to support the myth, the claim is irrational and illogical.
The myth stems from the fact that American cryptanalysts had cracked Japanese codes and gleaned messages indicative of hostile intent, but that did not specify the when and where of Japan’s aggressive designs. Warnings were issued to American commanders throughout the Pacific, but the ones in Pearl Harbor failed to take adequate precautions – as did Douglas MacArthur in the Philippines, who was also caught unprepared despite the warnings.
As to the myth’s illogic, while FDR saw Nazi Germany as the world’s greatest menace, and was busily rearming and preparing the country for what he deemed the inevitability of war against fascism, there is no causal nexus between allowing the Japanese to bomb Pearl Harbor and the US going to war against Nazi Germany. It was Germany that FDR wanted to fight, not Japan. The Japanese attacking the US would have resulted in war against Japan, not in war against Germany.
The only reason the US ended up in a war against Germany was because Hitler, to the consternation of his generals, declared war on the US when he had nothing to gain, and everything to lose from gratuitously adding to his enemies the world’s wealthiest country and greatest industrial powerhouse. Absent that irrational decision on Hitler’s part, there is little reason to think that Congress would have declared war against Germany, which had not attacked America.
Even if there had been a logical link between a Japanese attack on Pearl Harbor leading to war against Germany, FDR’s alleged goal of getting the US into the war would have been accomplished just as well if US forces had been prepared. A Japanese attack defeated by alert US forces would have still been an act of war by Japan. Roosevelt would still have gotten the war he supposedly sought, without thousands of American servicemen and civilians getting slaughtered. The US Navy could have ambushed the Japanese and sunk their fleet before it launched a single plane against Pearl Harbor, and its mere presence in the vicinity of Hawaii would have been sufficient indicia of Japan’s hostile intent to justify war.