Read my comments on why the American system has failed.Show me the specific quote from the OP that suggests any citizen being above the justice system. The issue is what powers and protections are there for the President within the Constitution.
It was a brave attempt to better the British system of the king being above the law.
But the brave attempt failed and now the chickens have come home.
There's only one solution and that is to unequivocally abandon the British system! PERIOD!
The way that Britain and the colonies did it was to exclude politicians, while 'supposedly' keeping the immunity for the crowned head. It hasn't been tested recently and it likely won't.