Redistricting and gerrymandering
Every ten years, following the national census, the boundaries of congressional and state legislative districts are redrawn to reflect population changes. This process — redistricting — is among the most consequential and least-watched exercises of political power in America.
Why redistricting happens
Congressional seats are apportioned among states based on population. Within each state, those seats must be divided into roughly equal districts. As people move — from rural areas to cities, from the Midwest to the Sun Belt — district lines must shift to keep representation proportional. After each census, states have two years to redraw their maps before the next election cycle. In most states, the legislature draws the lines and the governor signs or vetoes them.
What gerrymandering is
Gerrymandering is the drawing of district lines to advantage one political party or group over another. The term dates to 1812, when Massachusetts Governor Elbridge Gerry signed a redistricting plan that created a district shaped like a salamander — promptly dubbed a "gerrymander." The two basic techniques are "packing" (concentrating opponents into as few districts as possible so they waste votes on massive margins) and "cracking" (splitting concentrations of opponents across multiple districts so they are a minority in each). Both dilute the political power of the targeted group.
Partisan vs. racial gerrymandering
The Supreme Court has addressed both forms differently. Racial gerrymandering — drawing lines primarily based on race — is unconstitutional under the Equal Protection Clause and the Voting Rights Act. The Court has been more reluctant to rule on partisan gerrymandering, holding in 2019 that such cases present "political questions" beyond the reach of federal courts. State courts operating under state constitutions have been more willing to intervene.
Reform efforts
Many states have adopted or are considering independent redistricting commissions — bodies drawn from citizens, not politicians — to draw district lines. California, Arizona, Michigan, and Colorado, among others, now use such commissions. Supporters argue that removing the process from the direct control of legislators reduces the self-dealing inherent in the current system. Critics note that no commission is truly "independent" and that every map involves choices that advantage someone. The debate continues in legislatures and courtrooms across the country.