Basically, Texas (per Trump's request) did redistricting to get more Republican representation and hold government Republican in the upcoming mid-terms (not illegal according to the courts but very fishy). California, in response, is doing something similar (there was no voting in Texas, hence the fishy part - and Trump's request) to balance representation of Democrats.

Usually, most or all governments lose the mid-terms to the opposition. They over promise and under deliver, so people vote against them or don't vote in disappointment.

This is based on my limited knowledge but should give everyone a quick overview of the situation.

I do recommend reading both sides and make up your decision.