Now states are free to gerrymander as much as they want....

so new elections will become an exercise in futility because the outcome will be predetermined by the dominant political party.

Both Democrats and Republicans will be forced to gerrymander as much of their state as they can because it's their only hope for remaining in power. Any party who's who doesn't gerrymander and loses to the other party will be unlikely to ever regain power again because the new party will do it and prevent the previous party from ever winning again.

Perhaps this could affect Presidential and Senate elections too if states calculate votes by who wins each gerrymandered district instead of simply tallying the total votes.

The Republican controlled Supreme Court seems to indicate that it will always decide to eliminate Democratic institutions in favor of autocratic ones when they get the chance. If things continue in this direction they may actually achieve their true goal of a total Republican controlled autocracy where no citizen has any say in government policies.
The powers that be are working hard to eliminate American freedoms for you and your descendants.

I fear that this decision, along with Citizen's United, could be the beginning of the end of America as an open democracy.

I hope the new president can make a difference but chances are becoming slim with intense, computerized gerrymandering becoming the law of the land just as unlimited, corrupting election contributions being blessed by the Supreme Court and corporations being given the same rights as individuals have corroded the value of democratic elections.

Damn I wish I could be more upbeat about the future but things have been continuously sliding down for decades now and I don't see a clear way to stop it.