No tribal law can supercede that of a country.
Not true. Back in the '90s, a resident on a reservation near Hialeah, FL was accused of killing a woman outside the reservation. Because the murder was not on the reservation, the tribal police did not have to prosecute it nor did they have an obligation to hand over the person to the Miami-Dade police. This forced the Miami-Dade police to set up surveillance outside the reservation and while it took a while, the man finally ventured off the reservation and was promptly arrested. Point being that the Miami-Dade with all their power could not step on that reservation to get him nor could they make the tribal people hand him over if they didn't want to. Laws are laws and even the president should have to follow them.