In 2020, voters across the country will elect new state legislators and governors, and in many cases, these officials will play a direct part in drawing the district maps that govern elections for the next 10 years.
The process by which district maps are drawn is called redistricting. Every 10 years, the U.S. Census Bureau delivers detailed population datasets to the states. Redistricting authorities in the states use these datasets to redraw their congressional, state legislative, and even local district maps.
In 34 of the states conducting legislative elections in 2020, the legislatures themselves will play a significant part in the 2020 redistricting cycle. In eight of next year’s gubernatorial elections, the winner will have veto authority over state legislative or congressional district plans approved by legislatures.
The 2010 election and redistricting cycle can illustrate how elections impact the redistricting process.
In the 2010 elections, trifecta control (when one party controls the governorship and both chambers of a state’s legislature) changed in 12 states where legislatures were responsible for redistricting.
Before the elections, seven of these 12 states were Democratic trifectas; the rest were divided governments.
- Six states changed from Democratic trifectas to divided governments: Colorado, Iowa, New Hampshire, North Carolina, Oregon, Wisconsin.
- Five states changed from divided governments to a Republican trifectas: Alabama, Indiana, Michigan, Ohio, Pennsylvania.
- One state, Maine, changed from a Democratic to a Republican trifecta.
Of the six trifectas gained by Republicans in those elections, three remain as such: Alabama, Indiana, and Ohio. Democrats have regained three of the trifectas they lost: Colorado, Oregon, and Maine. The rest are divided governments.
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