Whichever PARTY is in power does it. The irony is that the Congressman, Gerry Mander abhorred & protested against the practice of solidifying blocks of power by changing boundaries...But others wound up putting his name to it.
Dems like to emphasize Diversity by splitting people into pigeonholed demographically small groups & refuse to recognize that the USA is already the most racially & culturally diverse nation in the world. Citizenship is what unites us into a nation, yet Dems continue to encourage an illegal invasion of foreign nationals & degrade our unity into bankrupted chaos & anarchy. Their job is to obey the Constitution ABOVE ALL OTHER CONSIDERATIONS.