The Pearl Harbor Attack At 70 & The Conspiracy Theories That Won't Die

The destroyer USS Shaw explodes after taking direct Japanese hits

Shortly after dawn 70 years ago today, Japanese warplanes launched an attack on Pearl Harbor, Hawaii, the largest U.S. military base in the Pacific. Within two hours, they had destroyed or damaged 18 warships and more than 200 aircraft, and killed 2,403 soldiers, sailors and Marines.

While contemporary accounts and historians called the attack a total surprise, questions that have never been completely answered soon arose, prompting conspiracy theories, chief among them that President Roosevelt was aware of the impending attack but did nothing to prevent it because it would be the pretext he needed to take the U.S. into war. Six decades on, those theories refuse to die.

Chief among the unanswered questions are these:

* Did the U.S. intercept Japanese messages long before the attack but failed to warn the brass at Pearl Harbor?

This question would seem to be especially pertinent because by the summer of 1940, the U.S. had cracked Japan's top-secret diplomatic code, which intelligence officers nicknamed "Purple."

Yet although several U.S. command posts received machines for decoding Purple, Pearl Harbor never did. Not that it would have mattered. This is because the Japanese never sent messages that hinted, let alone came right out and said, that Pearl Harbor was to be attacked.

Nevertheless, Washington was not blind to the possibility of an attack and General George Marshall had sent a message on November 27 stating that "hostile action possible at any moment. If hostilities cannot, repeat CANNOT, be avoided, the United States desires that Japan commit the first overt act."

* Did a U.S. seaman pick up signals from approaching Japanese aircraft and pass the information to the White House, which ignored it?

Possibly. John Toland promotes this theory in his bestselling book, Infamy. He asserts that a Navy electronics expert in San Francisco identified "queer signals" in the Pacific and using cross-bearings, he identified them as originating from a "missing" Japanese aircraft carrier fleet that had not been heard from in months and that the fleet was heading toward Hawaii.

Several experts have debunked this story. They assert that the signals were to the carriers from Tokyo and would have been useless in giving away their location.

Additionally, the seaman, later identified as Robert D. Ogg, flatly denied that he had said the signals were from the missing carrier force.

* Even if FDR did not know specifically of the impending attack, did he try to provoke the Japanese into attacking?

While the president did tell close aides that if the Allies were to be victorious the U.S. had to enter the war before Japan, there is not a shred of evidence to prove a conspiracy to goad the Japanese into attacking.

No fewer than 10 official inquiries were conducted after the attack.

All concluded that Japanese intentions and capabilities had been underestimated, key Army and Navy officials were incompetent, there was a lack of adequate manpower for intelligence, and excessive secrecy and unclear divisions of responsibility between the Army and Navy. A Navy vice admiral and Army lieutenant general were forced into retirement.