And if we hadn't cut off Japan's oil and rubber Pearl Harbor wouldn't have happened.
We can take this game back dozens of steps...
(Japan looked at Pearl Harbor the way we looked at surgical strikes a few administrations ago, and drone strikes today, a targeted, measured response, only aimed at combatants, and minimizing civilian casualties)
The lead up to war in the Pacific is convoluted and there were mistakes made on all sides. However, the imperialistic nature of the Japanese regime was overwhelmingly the primary cause. Left to their own devices they would have enslaved hundreds of millions of people and taken control of the entire region. The atrocities would have been horrific and would have continued for decades because this was one of the most racists cultures that ever existed.
There was no modern idea of trade partnerships that benefitted both parties - there was only conquest and theft. Those who deny such evil will be doomed to repeat it. We can forgive later generations, but they have a responsibility to acknowledge the truth because forgiveness depends on it.
In that respect it was very successful — far fewer civilian casualties than a typical bombing-run; having a military/civilian casualty ration of about 34:1. (About twenty times better than WWII rate… and that's counting the American UXO casualties.)
Pearl Harbor is not an atrocity: tragedy, yes; atrocity, no.
[Wikipedia: The civilian to combatant fatality rate in World War II lies somewhere between 3:2 and 2:1, or from 60% to 67%.]
[Wikipedia: Ninety minutes after it began, the attack was over, as 2,386 Americans died (48 - 68 were civilians, most killed by unexploded American anti-aircraft shells landing in civilian areas), a further 1,139 wounded.]