Japan's original strategy called for an attack on the Dutch East Indies (now Indonesia, a rich source of oil and other raw materials) with a possible strike at American bases in the Philippines to protect their flank. Once they had consolidated their conquests, they would confront the advancing Americans in a climatic sea battle in the Central Pacific. But Adm. Isoroku Yamamoto, Commander in Chief of the Combined Fleet, conceived of a much more daring plan. Having seen America's industrial might at first hand as a naval attache in Washington, he declared that Japan had no hope of winning a war with the United States "unless the U.S. Pacific Fleet in Hawaiian waters can be destroyed."
In January 1941, Yamamoto began planning a surprise air strike against the American battleships and carriers as they lay at anchor at Pearl Harbor. There was ample precedent for such a strike. Surprise was a cardinal principle of Japanese military doctrine, and such attacks had come at the beginning of wars with China and Russia. In 1932, during U.S. fleet exercises, Pearl Harbor had been successfully "raided" by carrier planes one quiet Sunday morning. And in November 1940, a handful of obsolescent British torpedo planes had devastated the Italian fleet as it lay at anchor at Taranto.
A diplomatic ballet -- designed to mask Japanese intentions -- unfolded in Tokyo and Washington as Yamamoto prepared for the attack. The Japanese navy's most experienced pilots and air crews were assigned to Plan Z -- as the operation was known -- and technicians were put to work developing armor-piercing bombs and torpedoes that would run true in the shallow waters of Pearl Harbor. Finally, on November 26, 1941, six carriers crammed with 425 planes and guarded by two battleships under the command of Vice Admiral Chichi Nagumo disappeared into the fog-shrouded North Pacific.
The following day Washington sent a "war warning" to the American commanders in the Pacific, including Kimmel and Lt. Gen. Walter C. Short, the Army commander in Hawaii, who was charged with the defense of the island. Negotiations with Japan had broken down, they were told, and an attack was expected on the Philippines, Malaya, Thailand or Borneo within the next few days. Although both commanders were ordered to execute "appropriate defensive deployment" there was nothing to indicate that Pearl Harbor was a target.
Short took no action except to mass his aircraft to prevent sabotage. Kimmel ordered a partial alert but failed to establish sustained round-the-compass aerial patrols. He considered sending the battle fleet to sea but decided to against it because the only two American carriers in the Pacific had been detached to deliver planes to the Marine garrisons on Midway and Wake islands. Torpedo nets were unavailable because the Navy Department was convinced torpedoes would be ineffective in the shallow waters of Pearl Harbor.
Smoke was still rising from the battered ships lying in the mud of Pearl Harbor when the search for scapegoats began. Short and Kimmel were relieved of their commands, yet, in vivid contrast, Gen. Douglas MacArthur escaped censure even though his forces were caught by surprise nine hours after the attack on Pearl Harbor. Obviously, the Pearl Harbor commanders were singled out as convenient scapegoats to cover inexcusable errors of commission and omission at almost every level of government.
There was plenty of blame to go around, and a cottage industry has been built on attempts to prove that Franklin Roosevelt had foreknowledge of the Japanese attack and deliberately sacrificed the Pacific Fleet to bring the United States into the war against Nazi Germany through the back door. Conspiracy theorists charge that the master plotter in the White House ignored clear signals of an impending attack on Hawaii to unite the American people behind him and then had the files sanitized to remove all traces of the conspiracy.
Pearl Harbor certainly rescued Roosevelt from an impossible dilemma, yet it is hardly likely that that he would have offered up the entire Pacific Fleet as a sacrifice when those same ships would be needed to win the war. Moreover, as far as the president was concerned, a war in the Pacific was the wrong war at the wrong time in the wrong ocean. The basic thrust of his policy was to keep Britain afloat, and a war with Japan would drain off men and material from operations against Germany, which he saw as the main enemy.
The conspiracy theory is also undermined by the lack of any assurance that even if Japan was provoked into an attack on the United States, war with Germany would result. Nothing in the Tripartite Treaty, which Japan had signed with Germany and Italy, required the signatories to come to the aid of the others in case of war. Japan used this loophole to escape joining its Axis partners in an attack on the Soviet Union, so why should Hitler assist his less-than-faithful ally?