December 7, 1941 was truly a date that will forever live in infamy but could the attack have been prevented? Some argue that if Japanese ambassadors met with Americans in Alaska to resolve diplomatic issues in November 1941 that war could have totally been prevented. During that time, relations were strained since the United States placed an embargo on Japan for their attacks on China. The U.S had significant interests there and as a result, Japan no longer received oil and iron from us. For that reason, I believe war was definitely imminent; it was just a matter of when and where it would begin. Japan, according to intelligence, was certainly building up a navy which was probably why we docked a significant portion of our navy at Pearl Harbor. The American government knew that Japan was a threat but radio codebreakers did not see a connection corresponding with an attack on Pearl Harbor specifically.
There was a specific message decoded from Japanese radio chatter on November 19th about the weather which would warn Japanese posts that relations were to be cut off. According to Historynet, “If Japanese-American relations were in danger, the forecast would predict ‘east wind rain.’ American code-breakers solved this message on November 28. Immediately, a frantic effort was made to pick up this broadcast.” Officials believe that “wind” meant that relations were cut which would suggest possible Japanese aggression. But no mention of an attack on Pearl Harbor.
Some intercepted radio traffic was alluding to movements of American ships, which is suspect in itself. But as mentioned by Historynet, “from August 1 to December 6, 59 such intercepts dealt with the Philippines and only 20 with Hawaii.” So it seemed more likely that our ships in the Philippines were in more danger. These movement details were thorough and one intercept shows that the Japanese consulate in Hawaii was gathering Intel on ships in Pearl Harbor. But again nothing implied an attack that the US saw possible on Pearl Harbor. Also even if the evidence was deemed credible that an attack was possible there was the matter of when it would occur.
Another intercept was decoded as “Climb Mt. Niitaka 1208.” “The 1208 in the message meant December 8, the attack date on the Tokyo side of the international date line. Mount Niitaka (Hsin-kao in Taiwan) was the highest peak in what was then the Japanese empire.” (Historynet) However, this specific message was not decoded until later. But it probably would have warned that a large scale attack was coming. Also other materials were later discovered that showed a Japanese oiler ship was ready to refuel ships on their way homeward after the attack on Pearl Harbor. If intelligence officers and codebreakers would have received these bits of information sooner, maybe the attack wouldn’t have been a surprise.
The Japanese seemed adept in hiding their intentions. As stated by Roberta Wohlstetter in her book Pearl Harbor: Warning and Decision, “‘We failed to anticipate Pearl Harbor not for want of the relevant materials, but because of a plethora of irrelevant ones.” The Japanese were never specific about their intentions and seemed to have our intelligence looking elsewhere for probable threats. The Japanese also never mentioned Pearl Harbor in their messages and their attack force maintained complete radio silence on their journey. It seems we didn’t know and couldn’t have known where Japan’s ships were located.
I have heard of theories that Roosevelt and officials in fact knew about the attack hours before it occurred. I am not sure of the truth of that theory but it makes one wonder. If he withheld information was it because it was in fact too late or was it for alterior motives? America was an isolationist nation, a “Sleeping Giant” so to speak but is it possible Roosevelt realized that a surprise attack would galvanize citizens to war to finally support our allies? I think it is a possibility because if Pearl Harbor was warned, the severity of the attack would probably have been lessened and not as shocking. Would a simple Japanese attack with no surprise have been enough to convince Americans to go to war? It’s all speculation about what could have happened but either way, war with Japan and the Axis powers seemed imminent regardless. Maybe the question is why we waited so long to join the war effort.