From Washington Post:
Just three states have approved new congressional maps for the next decade: Oregon, Maine and Nebraska. Forty-one states are still crowded around the drawing board.
But the patterns, and their political impacts, are already obvious. Where one party controls the process, it’s creating as little competition as mathematically possible. Where the power’s been handed to a nonpartisan commission, the maps may be more competitive than ever. …
But where nonpartisan commissions are drawing the maps, people with no particular stake in who controls Congress are finding it easy to draw competitive districts. In Colorado, where voters handed the redistricting process to a committee, draft maps keep the city of Denver mostly inside of the 1st District; doing so, and not drawing from its precincts to make other seats bluer, leaves the increasingly Democratic state with two swing seats and six safe seats divided evenly between the parties.