I don't see the treaty where Fort Sumner is ceded to South Carolina. Where's that one? I can see where treaties dealing with Panama are pointed out.So, should the US take back the Panama Canal Zone, based on your logic? Or is that different, because brown people?
The division of the country of Panama into two parts by the U.S. territory of the Canal Zone caused tension throughout the twentieth century. Additionally, the self-contained Canal Zone (the official name for the U.S. territory in Panama) contributed little to the Panamanian economy. The residents of the Canal Zone were primarily U.S. citizens and West Indians who worked in the Zone and on the canal.
Anger flared in the 1960s and led to anti-American riots. The U.S. and Panamanian governments began to work together to solve the territorial issue. In 1977, U.S. President Jimmy Carter signed a treaty which agreed to return 60% of the Canal Zone to Panama in 1979. The canal and remaining territory, known as the Canal Area, was returned to Panama at noon (local Panama time) on December 31, 1999.
Additionally, from 1979 to 1999, a bi-national transitional Panama Canal Commission ran the canal, with an American leader for the first decade and a Panamanian administrator for the second. The transition at the end of 1999 was very smooth, for over 90% of the canal employees were Panamanian by 1996.