There should be trials one day. For destroying what was once the largest Middle-Class in the world by shipping jobs overseas. Still others for starting unnecessary wars. Allowing toxic wastes to poison the water tables of whole States. For deliberately maintaining systems of discrimination, and economic inequality.
On, and on...
The crimes are many the criminals are many. The temptation to just hang or shoot them is great. However spilling blood just keeps the same deadly game going.
So some form of the "Truth, and Reconciliation" model must be used. Let all the truth out. Have them that caused war torture stole the futures of whole generations face their victims, and explain how, and why they did it.
Most will never repent, but on international media they would have confessed all they did. After this, and an entertaining "Perp Walk" they will be released given their pensions, and sent home to live out their lives as known civil, and war criminals.