separatism

A theory or doctrine which supports a state of separation between organizations, institutions, or other societal groups (e.g. between church and state) or between different political jurisdictions (e.g. a country and its former colony).

“She wrote an essay expounding the tenets of Scottish separatism.”

The practice of treating members of different societal groups in a politically, legally, or economically different manner.

“Apartheid was a government-enformed form of separatism in which people received unequal social benefits based on race.”