Neither the Hiroshima nor Nagasaki nuclear bombing was a “crime”. Invading Japan would have cost hundreds of thousands of US casualties, and millions of Japanese casualties - far more than the bombings cost.
WW2 was total war, and civilian casualties were simply part of the equation. The Japanese were ruthless butchers for the most part, and if Japan could have landed atomic bombs on the US it would have done so without hesitation. Japan certainly slaughtered countless civilians with no compunction.
The nuclear bombing of Japan was a regrettable necessity - nothing more.
The object is to win.