> international treaties that establish a supranational court system should not exist

ICJ and ECJ seem fine. I agree that the ICC is toothless (unless it’s investigating Africa for some reason). But if countries agree to its jurisdiction that’s basically glorified arbitration. The Philippine with Duterte show the benefits to a population to submitting to jurisdiction. I bet a lot of Americans being abused by ICE wish we had a check on our political leaders outside our own legal system.