Last month the Pennsylvania Supreme Court instructed the state’s Republican-led legislature to draw a new congressional map after finding the existing one was an illegal partisan gerrymander that violated voters’ right to participate in “free and equal elections.” On Friday, Republican leaders in the legislature submitted their new map for the governor’s approval. As directed by the Supreme Court, the new map is much more compact than the old one. Gone are the infamous convolutions that characterized the old map, earning nicknames such as “Goofy kicking Donald Duck.” The new districts generally respect county and municipal boundaries and don’t “wander seemingly arbitrarily across Pennsylvania,” as the state’s Supreme Court wrote. Unfortunately for Pennsylvania voters, the new districts show just as much partisan bias as the old ones.
You can demonstrate this using the precinct-level results of the 2016 presidential election: See which precincts are assigned to which districts under the new map, use those assignments to calculate the total presidential vote in each of the new districts and compare those figures with the vote totals under the old districts. That will give you a good sense of how the partisan makeup of the new districts compares to the old ones.
Brian Amos, a redistricting expert at the University of Florida, has done exactly that. Amos combined the new district maps with precinct-level returns compiled by cartographers Nathaniel Kelso and Michal Migurski.