Election shows how gerrymandering is difficult to overcome

With an election looming, courts earlier this year declared congressional districts in two states to be unconstitutional partisan gerrymanders. One map was redrawn. The other was not.

The sharply contrasting outcomes that resulted on Election Day in Pennsylvania and North Carolina illustrate the importance of how political lines are drawn — and the stakes for the nation because that process helps determine which party controls Congress.

Pennsylvania flipped from a solid Republican congressional delegation to one evenly split under a map redrawn by court order, contributing to the Democratic takeover of the U.S. House.