Japan is extremely poor in natural resources, and the situation was not much different in the pre-World War II era. Consequently, Japan had to depend on trade heavily to function as a modern nation, and it was a serious and vital issue for Japan to keep all crucial strategic resources, particularly oil, coming in to it from the outside world. If the route for Japan to obtain these materials was cut off, and therefore, the strategic resources were stopped from coming to Japan, there would basically be only two choices left for Japan. One is to lower the level of function as a modern nation to where it could meet the level of domestic productivity for natural resources. And two is to go out actively and find a way to gain what it needed to maintain its function as a modern nation. The conflict and negotiation between the US and Japan in the pre-World War II period illustrates a good example of the case and explains why Japan went to war against the US. The US, the biggest oil supplier for Japan at the time, imposed the oil embargo on Japan in July, 1941, and it helped the Japanese to make up their minds to fight against the Americans. Thus, in a way, the attack on Pearl Harbor was not a surprise one at all; it was a necessary result of the conflict and negotiation.
-from Arima, The Way to Pearl Harbor: U.S. vs. Japan in the American University's ICE Case Studies.
Do the Iranian mullahs have the backbone that the Japanese had? I guess we'll see.