Modern Thought has an interesting article by Phillip Henderson, which attributes intelligence failures primarily to selective interpretations that reinforce the predispositions of policymakers. Clearly this is part of the answer, but I believe it is an incomplete one. In particular the failure to pinpoint an attack on Pearl Harbor, which he includes in his confirming cases, resulted from a failure to acquire hard evidence that likely would have forestalled much of the damage at Pearl Harbor.
American intelligence on Japanese intentions actually was excellent. The United States knew perfectly well that Japan would attack. American policy deliberately had left Nippon with no alternative except virtual surrender of great power status. We may not fully have understood that their imperialism in Asia was designed to avoid the fate of China by copying the successful imperial policies of the European powers. However, we were aware that acceptance of Roosevelt's virtual ultimatum would have been equivalent to accepting European domination of Southeast and East Asia. The chief mystery is why General Marshall was out horseback riding on December 7 when he knew that an ultimatum would be delivered that morning.
Why was their no urgency in removing the fleet from Pearl Harbor? The answer to this is rather simple. Torpedoes do not explode in shallow water. At least no torpedoes that the United States knew of did. Therefore, an attack on Pearl Harbor would be a costly mistake that diverted the Japanese military from the oil and mineral wealth of Southeast Asia. The real intelligence failure was the failure to get information about Admiral Yamamoto's exercises with torpedoes that did explode in shallow water. If we had had that information, we would have understood that an attack on Pearl Harbor could not be discounted.
Many intelligence failures stem from a failure to ask the right questions. As an 18-year-old in the spring of 1939, I read in the Philadelphia Record of diplomatic travel between Russia and Germany. I was aware that the Western powers would like nothing better than for Hitler and Stalin to duel to the death. And it was also clear that Stalin would have liked nothing better than for Hitler and the democracies to destroy each other.
If, however, Hitler began by attacking Poland, Russia had to be bought off first, lest Hitler expend his forces against Russian troops fearful that the Nazis would not stop at the eastern Polish border. In the meantime, the French army, which was universally, although inaccurately, regarded as the best in Europe, would remain unscathed behind the Maginot Line.
By giving Poland a blank check, the Western powers removed Stalin's fear that Hitler's next move after Poland would be against the Soviet Union if he accepted a deal that gave him the eastern half of Poland. Thus, the pact was a win-win situation for the two powers. It did not take great intelligence on my part to infuriate a communist professor who was giving a lecture on socialist foreign policy by telling him that there was going to be a Nazi-Soviet pact.
If one observed Stalin's territorial gains during the pact, they all gave him space against Germany. Only David Lloyd George among Western leaders had the perspicacity to note this. …