Why did U.S. foreign policy force Japan to bomb Pearl Harbor in 1941?
First, we should note that many people would argue that US policies did not "force" the Japanese to attack Pearl Harbor. This is an interpretation, not a fact.
If the US policies did in fact force Japan to attack, it was because they forced Japan to seek an empire. Japan did not have much in the way of resources. In particular, they had not oil or iron. They imported much of both from the US. When the US cut off their supply of these things, Japan had to either attack Pearl Harbor (so the US could not oppose them as they took places like Indonesia) or to just give up and let the US tell them what to do. This choice forced them to attack Pearl Harbor since no country will willingly allow other countries to tell it what it can do.
1. When the Japanese decided to attack America, they knew that almost all of the immediate forces were naval. Hence, they decided to bomb pearl harbor, as it held the majority of the American naval forces in the pacific. By bombing the navy, they managed to cripple any efforts at an attack force following them immediately to retaliate.
2. Geography. They also decided to attack pearl harbor, but i believe the final decision was not made until approximately 2 to 3 days before the attack. Other targets included San Francisco, large coastal cities, etc. They decided upon pearl harbor because it was closer to japan than the U.S., and they would have less distance to travel. The closer they came to the U.S. coast, the larger the chance of being detected, and forced to turn back. Also, if they attacked the mainland, they would have to pass Hawaii on the way back, and by that time a force would be following them.
3. Deception. While the Japanese navy was steaming towards Hawaii, their ambassadors in D.C. were trying to convince the government that japan would not attack. Unfortunately for them, some people were getting suspicious. The fleet decided to attack then, instead of risking the longer journey to the coast.