Gerrymandering

Explanation

Gerrymandering is the deliberate manipulation of electoral district boundaries to create an advantage for a particular party. The two main techniques are "packing" (concentrating opposition voters into a few districts so they win those seats by huge margins but waste votes) and "cracking" (splitting opposition voters across multiple districts so they cannot win a majority anywhere). Gerrymandering is most prevalent in the United States, where state legislatures often control redistricting. It can produce dramatically unrepresentative results — a party winning 50% of votes but 70% of seats. Independent redistricting commissions (used in some US states, the UK, and Australia) are the main countermeasure.