Except the Trials where that precedent was supposedly established actually allowed a great many people to escape conviction using that exact defense, then the prosecution subsequently gave up on the trials altogether. The Nuremberg trials were a travesty of justice, not because the Allies set up kangaroo courts, but because in an attempt to avoid such accusations and through unbelievable prosecutorial incompetence they let almost every Nazi who was still alive run free.

What I'm getting at is, don't expect justice to magically administer itself.