Last updated: 8/7/2024

Abstract

In this analysis, we focus on 13 Republican-controlled legislative chambers in battleground states that were closely contested in 2020. We determine how many seats Democrats would have needed to win in order to gain control of these chambers, and how many more votes Democratic state legislative candidates would have needed to win the seats, looking specifically at the legislative districts where Democrats came closest to winning. In these districts, we also compile the total votes cast for Joe Biden, the Democratic presidential candidate at the top of the ballot, and the total votes cast for Democratic state legislative candidates, to calculate roll-off (i.e., how many more votes were cast for Biden than for the Democratic down-ballot candidate). By comparing the number of votes needed to win seats and the number of votes lost to roll-off, we find that the amount of roll-off is sometimes greater than the losing Democrats’ vote margin, and in several of the most competitive races, if Biden voters had also voted for their Democratic state legislative candidates, it could have changed partisan control of an entire chamber.

Background

Sister District’s previous study of votes to majority in 2020 found that partisan control of state legislatures is often decided by narrow margins—a handful of districts, or a few thousand votes. We have also demonstrated the prevalence of state legislative roll-off over time and in the most recent 2022 midterms, and in both studies we identified a clear partisan skew where Democratic down-ballot candidates are negatively affected by roll-off much more often than down-ballot Republicans. The purpose of this analysis is to integrate these two sets of findings, and show how the amount of roll-off, or the difference in votes for the top of the ticket versus the bottom, can have real consequences for the outcomes of state legislative elections and potentially determine which party controls the chamber.

Data and Methods

We collected 2020 vote totals by party in all state legislative districts from Secretary of State election records (via Ballotpedia) in the following chambers: Arizona senate; Florida house and senate; Georgia house and senate; Michigan house; Minnesota senate; North Carolina house and senate; Pennsylvania house and senate; Texas house; and Wisconsin assembly (house).

We first determined the number of seats Democrats would have needed to win in order to flip the chamber using Ballotpedia. We then identified the districts with the closest losing margins, and determined the total number of votes in the losing margins that decided the state legislative majority across all majority-making seats. For example, if Democrats needed 2 seats to win the majority, we identified the 2 districts in the chamber with the closest losing margins for Democrats and used the total loss margin from those specific races to determine how many votes Democrats would have needed to take the chamber. 

Using data from Daily Kos, we also calculated vote totals for Democratic presidential candidate Joe Biden in the same districts to determine the effects of roll-off, which is the difference between the number of people who voted for the candidate at the top of the ticket and the number of people who voted for Democratic state legislative candidates. Note: The roll-off numbers should be interpreted with care, since we cannot be certain that every voter who cast a vote for Biden would have also voted for their Democratic state legislative candidate (had they not rolled off).

Results

To illustrate the electoral consequences of the Democratic state legislative votes “lost” to roll-off in 2020, we selected 13 competitive, Republican-controlled state legislative chambers and determined the number of additional seats Democrats would have needed to win in order to gain the majority in each of these chambers. We then calculate the total number of votes it would have taken to win those majority-making seats, using the districts where Democratic state legislative candidates lost by the narrowest margins. Finally, we calculate the amount of roll-off, or how many more votes Joe Biden received than the Democratic state legislative candidates, in those same districts. The comparison is displayed in Table 1.

Table 1: Votes to Majority + Roll-Off in Battleground State Legislative Chambers, 2020

* Only half of the seats in the chamber were up for election in 2020.

Democratic-majority-making districts in 2020: AZ upper – Districts 17, 20; FL lower – Districts 2, 15, 21, 26, 27, 28, 41, 42, 58, 60, 64, 69, 72, 84, 93, 103, 105, 114, 120; FL upper – Districts 9, 20, 25, 37, 39; GA lower – Districts 35, 43, 44, 49, 73, 97, 104, 110, 119, 132, 138, 147, 151, 164; GA upper – Districts 8, 17, 23, 32, 37, 45, 56; MI lower – Districts 39, 45, 48, 104; MN upper – Districts 26, 34; NC lower – Districts 12, 37, 43, 45, 59, 74, 82, 83, 93, 98; NC upper – Districts 7, 9, 24, 31; PA lower – Districts 18, 26, 28, 33, 55, 105, 106, 143, 151, 160, 168, 176; PA upper – Districts 13, 15, 37, 49; TX lower – Districts 26, 66, 67, 92, 94, 108, 112, 132, 138; WI lower – Districts 4, 15, 21, 24, 30, 51, 55, 82, 85, 88, 92, 96

These results show concretely why roll-off matters: 

• To flip the Arizona state senate in 2020, Democrats would have needed to win just 2 more seats. In the 2 races that Democratic state senate candidates came closest to winning, the candidates lost by a combined total of 11,201 votes. In these same districts, 12,268 more votes were cast for Joe Biden than for the Democratic state senate candidates.
• In the Minnesota state senate, winning just 2 more seats in 2020 would have given Democrats control of the chamber. The Democratic candidates in these districts lost by only 1,813 votes. But there were 5,803 more votes for Biden than for these two Democratic state senate candidates.
• Democrats needed 9 seats to gain control of the Texas state house, and in the 9 districts with the narrowest margins, Democratic candidates lost by 21,566 votes. Again, in those same districts, 41,685 more votes were cast for Biden than for the Democratic state house candidates. 

Even in cases where the roll-off vote totals do not exceed the vote margins, it remains clear that meaningful numbers of Democratic votes are being lost to roll-off—in some cases the roll-off votes equal 50% or more of the vote margin that would have been needed to win. Furthermore, looking at the individual districts in this sample, we find that in 28 of the 104 districts (27%), the number of roll-off votes is greater than the vote margin that the Democratic candidate lost by.

Discussion

Overall, these results show that roll-off, or not voting in state legislative races, can have a serious impact on the outcomes—not just for individual elections but partisan control of entire chambers. In 2020, Democratic control of at least some of these competitive state chambers was not entirely out of reach. State legislative chambers are frequently won or lost in the races with the closest margins, where even a seemingly small amount of roll-off can make all the difference.