Here in my state, in the recent redistricting efforts, I have seen the Democratic Party redrawing lines to marginalize some communities, and make some seats even safer for Democrat candidates. Even locally in a previous precinct rearrangement, the local party moved lines to keep certain individuals in or out of certain precincts.
I observed similar behaviour when I lived in California.
Recent efforts across the nation by the Republicans seem pretty over-the-top.
A pox on all their houses.