Intelligence Failure at Pearl Harbor

Roberta Wohlstetter (1962) Pearl Harbor: Warning and Decision. Stanford: Stanford University Press.

How could American intelligence failed so consistently? This was a common question in the American news media after 9/11. The answers of Roberta Wohlstetter's 1962 book Pearl Harbor: Warning and Decision may provide some insight for modern readers, in answer to this question. Of course, Wohlstetter's analysis is applicable to a much older historical problem, namely how could America have failed to anticipate the threat of the Japanese bombings on Pearl Harbor. But her approach and answers provides an important warning to conspiracy theorists and intelligence apologists alike.

According to Wohlstetter, the intelligence clues that an attack on Pearl Harbor would take place only seem certain with the foresight of history. Many of the clues were "not merely ambiguous but occasionally inconsistent with such an attack" and only later did the mounting "dangerous" hints seem add up to the incontrovertible fact that there would be a surprise air attack on the naval base (388). Wohlstetter writes in response to those who state that the attack was obvious and a foregone conclusion, or worse that Franklin Delano Roosevelt knew about the planned bombing, but decided to ignore this to motivate Congress to allow him to declare war against Japan and Germany.

However, this is not to discount the fact that there were many human and bureaucratic errors that resulted in the American lack of preparedness, many of which seem quite surprising in light of the fact that the Americans were able to decipher Japanese codes and the Japanese engaged in such militant anti-American rhetoric and military shows of force (170). According to Wohlstetter, because the signals came from such diverse sources and because of the structural lack of communication between different government channels, it was often difficult to make coherent sense of the data that was being received. It was difficult to see the patterns in the intelligence that were emerging regarding the Japanese military movements, and thus the failure to do so was partially the result of human error, partly because of the poor intelligence gathering of the military, and partly because of the accepted fact that hostile enemy movements were often prone to reversal and designed to provoke panic, rather than true harbingers of future attacks.