As Texas Republicans move ahead with redistricting to protect or even expand the GOP’s slim majority in the US House, Democratic-run states, led by California, are pushing forward with their own efforts to draw new maps and add Democratic seats.

The Supreme Court has ruled that judges are powerless to review partisan gerrymandering. But courts can still enforce the Voting Rights Act provisions that protect minorities' voting power.

The two states' existing maps putting Democrats within just three seats of reclaiming a U.S. House majority in the midterms.