okay, i can see were you're coming from.
peral harbour was not the beginning of the war, just america's entry into it. japan had already been part of the war since 1940 when they occupied vietnam, which was a french territory at the time, and joined germany and italy's axis. pearl harbour was a year later. there were diplomatic discussion preceeding the attack, and they were not solved, so japan struck first. there was no formal declaration fo war, so 3000 people were killed in cold blood.
On July 27, 1945, the Allied powers requested Japan in the Potsdam Declaration to surrender unconditionally, or destruction would continue. However, the military did not consider surrendering under such terms, partially even after US military forces dropped two atomic bombs on Hiroshima and Nagasaki.
there was a complete direct threat to america, thats what a war is about. direct threat. in addition there was direct threat to america's allies, namely australia.
number 2, none of the axis abided by the rules of engagement, nor by any human's rights or pow agreements (i'm assuming that they were drafted before world war 2, if not, then there was nothing for america to transgress anyway). so why should america? those rules only work if both sides are willing to abide by them. if not, the civilian counts on your side rise much much higher, and in the end, you have to protect your own before someone else's.
