Voters like to think they choose their representatives. Gerrymandering can flip that around — letting representatives choose their voters by drawing the district lines in their own favor. Here’s how it works, and what can be done about it.
Where district lines come from
Every ten years the census counts the population, and states redraw their congressional and legislative district maps to keep them roughly equal in population. This redistricting decides which voters are grouped together — and whoever controls the pen has enormous power over the outcome.
The two basic tricks: packing and cracking
- PackingCram as many of the opposing party’s voters as possible into a few districts, so they win those by huge margins and "waste" votes elsewhere.
- CrackingSplit a bloc of opposing voters across many districts so they’re a minority in each and can’t win anywhere.
Used together, these let mapmakers win a large majority of seats with a minority of the statewide vote.
Partisan vs. racial gerrymandering
The law treats two kinds very differently:
- Racial gerrymandering — drawing lines to dilute the voting power of a racial group — can violate the Constitution and the Voting Rights Act.
- Partisan gerrymandering — drawing lines for party advantage — has been held by the Supreme Court to be largely beyond the reach of federal courts, leaving it to states and Congress.
What can be done
Reform efforts focus on who draws the maps. A growing number of states have handed redistricting to independent or bipartisan commissions instead of the party in power. Other proposals include clearer standards for compact, fair districts and stronger transparency.
Frequently asked questions
What is gerrymandering?
Drawing electoral district boundaries to favor one party or group, often so that representatives effectively choose their voters rather than the other way around.
What are packing and cracking?
Two core tactics: "packing" concentrates opposing voters into a few districts to waste their votes; "cracking" splits them across many districts so they can’t form a majority anywhere.
Is gerrymandering illegal?
Racial gerrymandering can be illegal under the Constitution and the Voting Rights Act. Partisan gerrymandering has largely been left by the Supreme Court to the states and Congress to address.