When the Japanese attacked the American naval base at Pearl Harbor on December 7th, 1941, the American public was stunned. While not yet a state, Hawaii was a territory of the United States, and the base there was one of the most important in the Pacific. The attack of course was the catalyst that drew the United States into the war, not only in the Pacific, but also in Europe. For the American public, these events were shocking and sudden. Yet for those familiar with the situation and in positions of power in the War Department, State Department, and the White House, the surprise should not have been much of a surprise at all.
The tactical situation in the Pacific was building up to a crescendo. Over the past decade, they had invaded, exploited, and “colonized” most of their neighbors, starting with Manchuria in 1931, and continuing with the brutal invasion of China in 1937. They had also occupied Korea since 1910 and French Indochina since September of 1940 (resulting in an agreement with the Vichy government). Most of these had involved surprise attacks.
There was also a precedent for Japan attacking United States vessels without provocation and then claiming that they had mistaken them for enemy vessels. The USS Panay, a United States gunboat that was part of the United States Navy’s Yangtze Patrol, was evacuating Westerners from Nanking on December 12th, 1937 when she was attacked and sunk by Japanese aircraft; three were killed and many were wounded. The Japanese government took responsibility for the attack while still claiming it was an accident, and paid a settlement to the U.S. Government. At the same time, the U.S. Navy had decrypted Japanese communications during the attack which made it clear that orders had been given and the incident was no mistake.
As 1941 unfolded, so did events that made war with the United States inevitable. After Japan invaded French Indochina, a move that an ordinary French government would never have allowed but a Nazi-controlled Vichy government would, the United States embargoed all oil going to Japan. This made it necessary for Japan to procure another source of oil. Japan believed that any further incursions to the south would provoke an American response. With the belief, then, in mind, a pre-emptive attack on the United States was considered necessary. At the same time, the United States, noting the escalating tensions, moved much of the Pacific fleet from San Diego to Pearl Harbor. In moving the fleet to such a forward position, it is clear that there was an expectation of eventual hostilities with Japan.
The United States had also successfully decrypted the most important Japanese ciphers, including the diplomatic channel, called ‘purple’, as well as the Japanese Navy’s code. One problem, however, was the backlog of unread messages. There were not enough trained linguists available to handle the volume of messages. Some did suggest possible attacks on the United States, though it is claimed that Pearl Harbor was never expressly mentioned. However, surely, on the basis of even vague claims about possibly attacking the United States, closer attention should have been paid to potential targets other than the Philippines, particularly on the basis of where the Japanese could do the most damage in a surprise attack, given what was already known about Japanese military, and particularly naval, tactics.
There were also statements given by high-ranking people and those close to Roosevelt after the war indicating that it was the President’s intention to provoke Japan into firing the first shot in order to push the United States into the war. Vice Admiral Frank E. Beatty later said of Japan, “We were forcing her so severely that we could have known that she would react toward the United States. All her preparations in a military way—and we knew their over-all [sic] import—pointed that way.” (Beatty 1954). Roosevelt’s Administrative Assistant at the time, Jonathan Daniels, is also quoted as saying, “The blow was heavier than he had hoped it would necessarily be. But the risks paid off; even the loss was worth the price. " (Leighton, Simon and Schuster 1949). Secretary of War Henry L. Stinson’s diary entry from December 5th, 1941 also indicates a certain degree of awareness on the part of the United States government. He recounts a meeting that day with Roosevelt in which they discussed “how we should maneuver them [the Japanese] into the position of firing the first shot without allowing too much danger to ourselves.” All of these things indicate that the United States, while not aware of the specifics of the attack, knew an attack was coming somewhere in the Pacific. Stinson would later complain that Pearl Harbor had been warned of the possibility of an attack, yet was unprepared for one.
All of this evidence suggests that an attack somewhere was inevitable, and that those in positions of power knew it. To them, Pearl Harbor, while perhaps not the specific location they expected the attack to come at, was surely not a surprise. They were well aware they had pushed Japan into a corner with the oil embargo, and knew that they would be pulled into war. They simply chose to let Japan fire the first strike. While Pearl Harbor was probably not where they expected it to come, they certainly should not, and probably did not, rule it out.
Vice Admiral Frank E. Beatty, “Another Version of What Started the War with Japan”, U.S.
News and World Report, May 28, 1954, p. 48.
“1941: Pearl Harbor Sunday: The End of an Era”. The Aspirin Age - 1919-1941, edited by
Leighton, Simon and Schuster, New York, 1949, page 490.