In the 44 states with state legislative elections on Nov. 3, 2020, there are 5,875 state legislative seats on the ballot.

This year, 4,994 incumbents sought re-election.[3] 20.4% (1,017) had a contested primary. 79.6% (3,977) advanced to the general election without a primary challenge.

• 79.6% of incumbents seeking re-election this year advanced to the general election without a primary.
• 20.4% (1,107) of incumbents had a contested primary this year. This includes 20.6% of Democratic incumbents (497) and 20.3% of Republican incumbents (519).
• Wyoming is the only state where over 50% of incumbents seeking re-election had a contested primary.
• In seven states, less than 10% of incumbents seeking re-election had a contested primary.‍

The five states with the highest percentages of incumbents in contested primaries include:‍

1. Wyoming 2. West Virginia 3. California 4. Alaska 5. Arizona‍

The five states with the lowest percentages of incumbents in contested primaries include:‍

44. Connecticut 43. Maine 42. Iowa 41. Colorado 41. North Dakota‍

The maps below show a partisan breakdown between Democratic and Republican incumbents. States shaded gray did not hold state legislative elections in 2020.

For the Democratic incumbents' map, a darker shade of blue indicates a higher percentage of Democratic incumbents in contested primaries, while a lighter shade of blue indicates a lower percentage. The states with the highest percentages of Democratic incumbents in contested primaries in 2020 were West Virginia, Washington, Hawaii, California, and Tennessee. In four states—Idaho, Nebraska, North Dakota, and Utah—there were no Democratic incumbents in contested primaries.

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For the Republican incumbents' map, a darker shade of red indicates a higher percentage of Republican incumbents in contested primaries, while a lighter shade of red indicates a lower percentage. The states with the highest percentages of Republican incumbents in contested primaries in 2020 were Alaska, Wyoming, California, West Virginia, and New Hampshire. In three states—Hawaii, Rhode Island, and Delaware—there were no Republican incumbents in contested primaries.

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Historically, around 12% of state legislative incumbents have lost primary elections, and another 8% have been defeated in general elections.

As of Sept. 4, 2020, 128 incumbents have been defeated in primary elections.

43 Democratic incumbents were defeated. In other words, 89.6% of all Democratic incumbents who have run in a primary won.

85 Republican incumbents were defeated. In other words, 81.4% of all Republican incumbents who have run in a primary won.

This story was republished with permission from Ballotpedia.org.