Liberals as well as conservatives have not understood or lack the courage to say that the melting pot didn't melt, which led to multiculturalism, but that hasn't worked either, because real human nature is genetically ethnocentric, even xenophobic, as well as being kin-centered, gender defined, age-graded, heterosexual marriage-making, hierarchical, with group-selection as the primary unit of selection.
Multiculturalism would have worked if the various cultures had linked their race to their own territory or ethnostate; defining cultures by creed or ideas alone with such unreal ideas as egalitarianism is not enough to offset the reality that multicultural multi-ethnic societies are a zero sum game where the gain of one ethnic group is offset by the loss of another ethnic group, with much cruel social discord in the process. Ethnostates are in harmony with the biological origin of social behavior and in accord with real human nature.
Although now just rising again, identity politics will continue to ascend, identifying with ethnicity, nationality, race, culture and faith is the world's future. People will see that diversity within the same state is not our greatest strength but is our greatest weakness. A true natural rights or civil rights movement would promote an ethnopluralism of ethnostates for all groups, black, white, brown, yellow, or red, with each ethnostate protected from marauding imperialists, global businesses, supremacists, Marxists, etc., with a defensive federalism. An ethnopluralism of ethnostates could be established legally in the United States with our constitutional separation of powers and states.