[jabl]

Certainly all of the major combatants of WWII have blood on their hands and committed what would certainly today be called atrocities and war crimes. That being said, there's certainly massive differences in motivation and scale.

For that reason, Imperial Japan certainly ranks right up there together with Nazi Germany as the most evil regimes in recent history, and the US of that era does not (saying this as a non-US'ian who is generally pretty critical of the post-WWII foreign policy adventures the US has gotten itself involved in).