Primaries for state legislative incumbents in states with trifectas have become more competitive since 2016. A trifecta happens when one political party holds the governorship and majorities in both chambers of the state legislature. In 2016, the percentage of state legislative incumbents facing a primary challenger was 20.6%. In 2018, it was 21.9%, and in 2020, it was 20.4%. In 2022, that percentage increased to 26.8%.

Ballotpedia uses the number and percentage of incumbents in contested primaries to help determine the overall competitiveness of an election cycle. 

Among Democratic trifectas, Rhode Island saw the most change in competitive primaries between 2016 and 2022. Democratic primaries saw 19.8% of primaries be contested in 2016. That percentage increased to 23.3% in 2018, 28.9% in 2020, and 33.7% in 2022. Republicans in the state had zero contested primaries from 2016 to 2020, but 7.7% of primaries were contested in 2022. 

Connecticut saw the least change in competitive primaries between 2016 and 2022 among Democratic trifectas. Democrats saw 8.3% of primaries be contested in 2016. That percentage fell to 6.0% in 2018, 4.7% in 2020, and 2.9% in 2022. Republicans in the state saw 2.9% of primaries be contested in 2016. That fellow to zero in both 2018 and 2020. In 2022, 1.9% of Republican primaries were contested in the state. 

Among Republican trifectas, Idaho had the most change in competitive primaries between 2016 and 2022. Republicans saw 38.0% of primaries be contested in 2016. That percentage increased to 40.0% in 2018, 39.4% in 2020, and 73.8% in 2022. Democrats in the state saw 5.9% of primaries be contested in 2016. In 2018, 7.1% were contested. In 2020 and 2022 zero Democratic primaries in the state were contested.

Tennessee saw the least change in competitive primaries between 2016 and 2022 among Republican trifectas. Republicans saw 31.3% of primaries be contested in 2016. That fell to 24.6% in 2018, 20.7% in 2020, and 13.5% in 2022. Democrats in the state saw 30.8% of primaries be contested in 2016. That percentage increased to 35.0% in 2018 and 38.5% in 2020, and it fell to 20.8% in 2022.

The earliest confirmed primaries for the 2024 state legislative regular election cycle will be happening on March 5, 2024. The first filing deadlines for those primaries are scheduled in December 2023.