Japan wasn't looking for a fight. The US imposed sanctions on Japan because of its aggression against China. There were negotiations on what Japan should do, but the US had rather far-reaching demands which Japan would not or could not agree to, which is what led to the war.
Of course, these are just the surface reasons. The real reasons are the same as why the US thwarted Germany's attempt at European hegemony in 1917 and 1941, and did the same for the Soviet Union during the Cold War. The US does not want any country to be a regional hegemon that could then potentially cause trouble for the US, militarily, economically, etc.
Japan wasn't looking for a fight. The US imposed sanctions on Japan because of its aggression against China. There were negotiations on what Japan should do, but the US had rather far-reaching demands which Japan would not or could not agree to, which is what led to the war.
Of course, these are just the surface reasons. The real reasons are the same as why the US thwarted Germany's attempt at European hegemony in 1917 and 1941, and did the same for the Soviet Union during the Cold War. The US does not want any country to be a regional hegemon that could then potentially cause trouble for the US, militarily, economically, etc.