State legislators and U.S. House members are elected by district. The composition and shape of those districts are updated each decade after the census. Often, the political party in power when districts are updated creates or redraws districts to maximize its advantage. This process is commonly known as partisan gerrymandering. It results in significantly less electoral competition. New mapping technologies have enabled political parties to even more effectively manipulate district lines in their favor down to the block or household level. The Supreme Court has generally allowed partisan gerrymandering to stand. In 2018, the Supreme Court allowed to stand maps that were drawn in favor of one party in North Carolina, Wisconsin, and Maryland. It did not, however, rule on whether partisan gerrymandering is legal.

A similar practice, racial gerrymandering, in which legislators dilute the voting power of certain racial and ethnic groups, is illegal under the Voting Rights Act. However, the Supreme Court has allowed some practices that advocates have argued are racial gerrymandering. In 2017, it blocked North Carolina’s entire congressional district map. It ruled the map was illegally racially gerrymandered. However, in a similar case in 2018, the Court allowed to stand most of the Texas state legislature and congressional district maps despite allegations of racial gerrymandering. The Court only blocked one particularly race-based Texas legislative district.

Some states have tried to reduce partisanship in the creation of congressional and state legislative districts. Independent nonpartisan or multiparty commissions are tasked with this job. Arizona and Iowa are two states that have used such redistricting systems. The resulting legislative districts are compact, contiguous, and reflective of their communities. In both states, bipartisan commissions that do not include legislators, lobbyists, or potential candidates draw districts based on communities of shared interest rather than on incumbency or party affiliation. Similarly, Californians passed an initiative in 2008 to establish an independent citizens’ commission to redraw legislative districts, which has helped to decrease gridlock and hold legislators more accountable. In 2015, redistricting reform efforts were given a significant boost when the U.S. Supreme Court upheld the constitutionality of an Arizona ballot initiative to remove state legislators from the process of drawing district lines in Arizona State Legislature v. Arizona Independent Redistricting Commission.


Redistricting procedures

States should create a transparent and nonpartisan redistricting process. It should be led by an independent and diverse commission. The independent commission should include representatives from historically disadvantaged racial and ethnic groups and other communities that have faced historical patterns of discrimination.

The redistricting process should provide a meaningful opportunity for interested parties and the public to participate.

Legislative districts should:

  • have equal populations;
  • comply with the Voting Rights Act;
  • be contiguous;
  • respect communities of interest, city and county boundaries, and visible geographic features; and
  • be geographically compact.