There are 206 pivot counties in the country-those that voted for Barack Obama (D) in both 2008 and 2012 and Donald Trump (R) in 2016. On November 6, 2018, 87 of the nation’s 99 state legislative chambers held regularly-scheduled elections for 6,073 seats. Of those, 453 state house districts and 138 state senate districts intersected with pivot counties. These 591 state legislative districts accounted for approximately 10 percent of all state legislative districts up for election in 2018.
Sixty-one districts switched partisan control in the 2018 elections. The elections resulted in a net change of 19 seats in favor of Democrats. The most common changes were:
- Republican to Democrat: 31 districts
- Democrat to Republican: 20 districts
- Split districts to all-Democrats: 10 districts
Democratic candidates for state legislatures in districts that intersected with a pivot county won a net total of 19 seats (3.2 percent of the total they controlled going into the election). Nationally, the party gained 308 seats (9.7 percent of the total they controlled going into the election).
Republicans lost a lower percentage of these seats than they did nationally, 3.3 percent to 7.2 percent.
Across the country, Democrats gained control of six state legislative chambers from Republicans, while losing one chamber (Alaska House) to a power-sharing agreement.