Pearl Harbor struck a country satiated with war's alarms. True, we had put through the draft and had actually reached the shooting stage with German submarines. But as a people we were still talking of war, without really accepting its imminence. Then, into our national complacency, came a surprise blow at our strongest point!
We underestimated Japanese military power. So far as military and naval estimates were concerned, Japan had to be judged largely on her past record. Power cannot be gauged solely on strength reports, even if actual strength be known. Japan's war record was not impressive. She had fought but one great power (if the Russia of 1904-1905 can be so rated), plus a push-over against an isolated German Colony. Most indicative of all were the four years before Pearl Harbor in which she had waged active warfare in China. We knew pretty accurately China's deficiencies in modern equipment, resources, and training. Our maps and time scales, as we followed the war, clearly indicated a low rating for Japanese military prowess when judged by modern standards.
We had a yardstick. No better measure exists of what a power plant can do, if you cannot put your own gauges on it, than what it has done. We had no reason to doubt our yardstick's approximate accuracy. Yet it was wholly false.
I remember an incident that happened a short time before Pearl Harbor. We feared that the Japanese forces in Indo-China might advance on the northern end of the Burma Road, at Kunming. Secretary Stimson asked me how long such a movement would take. Military Intelligence had considered the terrain and the opposing forces, and applied its yardstick. I accordingly replied, "Three months," and stuck to it when the Secretary tried to shake me. Compared to what the Japanese later did in Malaya, Burma, and the Philippines, my estimate for a Kunming advance was rather like assigning to a race horse the speed of a Percheron. The efficiency of Japanese military power, measured in space and time, in the six months between Pearl Harbor and Midway surprised the world.
Japanese ability to attack Hawaii, or alternately Panama or the West Coast, was primarily a naval problem. Unfortunately, our Navy underestimated Japanese sea and sea-air power even more than we in the Army underestimated the efficiency of their land and air forces. The Japanese Navy had seen even less of modern warfare than had the Japanese Army. No yardstick, true or false, could be applied. Whether because or in spite of that, the Japanese Navy was held in low esteem by our naval authorities. I remember Admiral Kelly Turner expressing in a British-American staff conference, six months before Pearl Harbor, his confidence in our ability to hold the Japanese Navy in home waters simply by having our fleet cruise in the mid-Pacific. I suggested that that would simply be "shadowboxing"—to the Admiral's annoyance, I fear. There was also the flat statement of Admiral Kimmel's war plans officer that there would "never" be an attack on Pearl Harbor by air. More specifically, the temporary detachments of carriers and cruisers from the main body of the Pacific fleet, at least tacitly approved by the Navy Department, almost coincidentally with their November war warnings, were practical reflections of the Navy's thinking on the possibility of Japanese major operations at sea.
Another important factor entered, almost to the last, into our estimates. It was the question of whether or not Japan would, on her own initiative, immediately involve us in war on the termination of her diplomatic conference in Washington. It became evident in the fall of 1941 that that conference would probably end without agreement. Our increasing economic pressure on Japan, plus the militaristic cast of the government that then came into power there and their partial loss of face in China, spelled a probable resumption of their policy of conquest. In what direction would the Japanese strike, and against whom?
There were many reasons, political and economic, to suppose that they would strike to the south. They already occupied Indo-China, under a thin veneer of legality. Beyond lay the riches of Malaya and the East Indies. Oil and rubber they particularly needed. There were also possibilities in the direction of Australia, Burma, and India.
That was, indeed, the line they took. It meant unprovoked war with the British and the Dutch, but not necessarily with us. We assumed that they knew the strong feeling in this country against involvement in war. "America First" was still abroad in the land, and very vocal. Crippling strikes threatened. Even in our new Army, bewilderment and discontent had coined the slogan "Over the hill [desertion] in October." We had lately saved that Army from complete disintegration by only a single vote in the House of Representatives!
Had Japan not attacked us when the Washington conference failed, there were but two courses of action that could have resulted in our interference with her policy of conquest. The President might have persuaded Congress to declare war, or he might have interposed U.S. forces in the path of the Japanese advance. The Administration's difficulties would have been great and its success problematical in either case. And how the isolationist elements in the country—the "Hearst-McCormick-Patterson Axis," "America First," and others—would have howled! American lives to be sacrificed in defense of British and Dutch colonies, and Siam! All this the Japanese must have known. They certainly missed a bet, once they realized that their negotiations in Washington would fail, in not going about their southern business and leaving us out on a limb.
Through "magic," our code-breaking device, we read a strong hint along this line to Tokyo from Ambassador Nomura in Washington. And he was right; for, whatever we did, the Japanese stood to gain time for the seizure and consolidation of their southern conquests, and the still greater advantage, in the long run, of fighting an America torn by dissension. They chose, instead, to bring us in at once, and by so treacherous an attack that complete unity in our war effort was instantly assured. We underestimated their war power, yes; but their fundamental failure to understand America and our potential in a long war (also pointed out to them by their Ambassador) was colossal.
It has been argued that the Japanese were bound to attack our fleet on resuming their policy of conquest because it constituted an intolerable strategic threat on their flank. The fleet was certainly an important element in Pacific strategy, and its damage or elimination was highly desirable from the Japanese point of view. But as a matter of fact, it was not an immediate menace to Japan, nor could it have seriously deterred her in the early months of whatever campaign she might decide to initiate behind the shield of her mandate islands. For our fleet, in any operations in the Far East, would have been distinctly inferior to the Japanese in air and sea power and particularly in logistic support.
We had no bases beyond Hawaii capable of handling the fleet. We lacked the "train," the great force of supply and repair ships, that would be necessary for such distance operations. This also the Japanese must have known. Not even the most extreme misconception as to the relative efficiency of the opposing forces would have led our fleet so far from its base for a considerable period of time. Or if it had, Admiral Yamamoto could have solved his problem still more tragically for us.
Neither factor discussed above—our underestimate of Japan's war power or our evaluation of the advantages that would accrue to her if she put on us the onus of making war—neither consideration caused us to ignore the possibility of an immediate Japanese attack on us when the Washington conference terminated, or the probability that we should eventually be involved in her war. The war warnings of November 24 and 27, together with the many discussions which culminated in the unprecedented appeal of President Roosevelt to the Japanese Emperor, clearly show this. It was also abundantly clear that the decision to bring us in initially or to put the onus on us rested solely with Japan.
The high command of our Army and Navy thought they had prepared for either eventual or immediate war, so far as it was humanly possible to do so. But still it was difficult to predict, and indeed we did not predict that the Japanese would commit so great a blunder as Pearl Harbor, gratuitously unifying the war spirit and potential of America. We overestimated their intelligence.
That blunder in the realm of high policy eventually cost Japan her empire. But that was not all. On the lower plane of tactics the Japanese decision to attack Pearl Harbor by surprise involved enormous risks. As General Marshall later testified: "A surprise is either a triumph or a catastrophe. If it proved to be a catastrophe, -the entire Japanese campaign was ruined."
Our fleet and fortress together constituted what probably was, at that time, the most formidable strong point in the world. The fortress, with its garrison reinforced, had great firepower and a not inconsiderable air force. "'The presence of the fleet," General Marshall had told the President, "reduces the threat of a major attack." Had the fleet been held together and deployed in adjacent waters, it could have retained sea supremacy. Six months later, at Midway, weaker forces, supported by far fewer land-based planes, decisively defeated a Japanese fleet much superior to the hit-and-runners that bombed Pearl Harbor.
It is true that most of our air strength was not on the alert or otherwise available when the attack came; but the Japanese had to assume it would be, as of course it might have been. Our radar detection stations closed down after 7.00 A.M., but that again the Japanese could hardly have known. Though we could not have matched the Japanese carrier-borne air force, plane for plane, we had the great potential advantage of near-by land bases for much of our force. Hostile planes had also to count on facing well-equipped and presumably well-prepared antiaircraft batteries, both afloat and ashore. Consideration of high policy aside, a Japanese attack on such a place-of-arms, under alert commands, was, on the face of it, improbable.
Our reasoning was correct. The flaw lay in that phrase "under alert commands."
The Hawaiian fortress and naval base were built with but one potential enemy in view, Japan. Studies concerning the Japanese bore on their military characteristics. It was well known that they were given to treachery and surprise. The President himself, less than a fortnight before Pearl Harbor, remarked that "the Japs are notorious for making an attack without warning."
The strategic importance of Hawaii, coupled with the possibility of surprise on the part of its sole potential enemy, was with us always, whatever might be the probabilities of other Japanese action in any given situation and at any given time. The answer could only lie in Hawaiian readiness to meet an attack, whenever and however made. That had been Army teaching for many years—coupled with the devout hope that we might get some warning of war.
The type of attack actually made—the how of it—had by no means been overlooked by the military. Many years before 1941 our fleet had made, in maneuvers, an attack on Pearl Harbor very similar to the actual one. In the early and middle 1930's the possibility of such an attack had been seriously discussed. General Drum, when in command in Hawaii, had had a long correspondence with the War Department on the subject. Even the "vacant sea," that area between the great Pacific traffic lanes through which an attacking force could approach Hawaii undetected, had been marked down in our defense studies.
In January, 1941, the Secretary of the Navy listed the first three Hawaiian dangers "in order of importance and probability... (1) air bombing attack, (2) air torpedo plane attack, (3) sabotage." The Secretary of War concurred. Generals Marshall and Short corresponded on the subject that spring, and the former pointed out that the first six hours of hostilities would probably be decisive in Hawaii. In March the two senior air officers there, General Martin and Admiral Bellinger, made a defense study in which they practically called the turn on what later happened. And in May General Short wrote the Chief of Staff describing joint maneuvers he had held with the fleet, the theme of which was the defense of Hawaii from a carrier-borne air attack.