The Election Before Election Day
Gerrymandering is the practice of drawing electoral district boundaries for partisan advantage. District maps are generally revised after each ten-year census, creating a recurring opportunity to reshape political power.
The term dates to 1810, after a Massachusetts redistricting map associated with Governor Elbridge Gerry was said to resemble a salamander.
Cracking and Packing
Two techniques explain the basic strategy. Cracking spreads opposition voters across several districts so they remain below a winning share in each one. Packing concentrates opposition voters into a small number of districts, allowing them to win those districts by huge margins while leaving fewer of their votes useful elsewhere.
Both methods create wasted votes—ballots that do not help produce additional representation.
Precision Politics
Modern mapping software and high-speed computing have made district design far more exact. Since 2010, parties have used these tools in efforts to control state legislatures and congressional representation, sometimes creating maps designed to preserve power for years despite changing public opinion.
In Pennsylvania, one cited map gave Republicans a virtual lock on 13 of 18 congressional districts even in elections where Democrats won most of the statewide congressional vote.
The Courtroom Boundary
Challenges to partisan gerrymandering reached the Supreme Court, including Vieth v. Jubelirer in 2004. The Court’s refusal to clearly establish a constitutional standard has, critics argue, emboldened increasingly partisan maps.
Gerrymandering can also affect minority voters, either weakening their influence by dispersing them or concentrating them into districts where they can elect representatives sharing their background.
A map may look neutral on paper. But once its lines are drawn, the contest may already be tilted.