Wikipedia says that the US genocide of Native Americans numbered somewhere between 30-50K people over 120 years, some of those in military conflicts. In comparison in the Rape of Nanking, the Japanese murdered 50-300K. And averaged 300-500K civilians murdered <i>per month</i> between 1937 and 1945.<p>By 1941 Japan had no reason to believe the US was in any way expansionist. There had been 20 years of isolationist rhetoric from both political parties and almost no public support for intervention in wars abroad.