The Republican Party has quickly moved toward filling the Supreme Court seat left vacant by the passing of Justice Ruth Bader Ginsburg. Even before President Trump announced his nomination of Amy Coney Barrett, Senate Majority Leader Mitch McConnell (R-Ky.) vowed that Trump’s nominee would receive a vote on the Senate floor.

The swift movement may help secure a 6-to-3 conservative majority on the high court. In addition, many Republicans are hoping that a confirmation battle may give the party a much-needed boost in its fight to maintain their majority in the Senate.

Yet there is also potential for backlash. A New York Times-Sienna College poll conducted just days before Ginsburg’s death found that when asked which candidate they trusted to do a better job of choosing a Supreme Court justice, likely voters in the key Senate battleground of states of Arizona, Maine and North Carolina were all more likely to select Joe Biden over Trump.

A Reuters-Ipsos poll conducted after Ginsburg’s death also suggests possible trouble for Republicans. This nationwide poll found that 84 percent of Democrats and 49 percent of Republicans surveyed agreed that Ginsburg’s replacement should be selected by the winner of the election.

Thus it seems that those Republican senators engaged in tough reelection battles may want to consider public opinion about Barrett in deciding how to handle the coming nomination battle and vote. Indeed, such a proposition is supported by our research. Our investigation of the connections between Supreme Court considerations and voting in Senate elections finds evidence that voters can and do punish their senators when they disagree with those senators’ confirmation votes.

How we did this research

Here we focus on just one of the three studies we conducted. This study examined voting behavior in the 2018 Senate elections. These elections occurred after the Senate confirmation votes for Justices Neil M. Gorsuch and Brett M. Kavanaugh. As such, we are able to test whether voters’ agreement with their senators’ votes on these two confirmations is related to whom they vote for in the next general election.

We took advantage of the 2018 Cooperative Congressional Election Study (CCES), a publicly available survey of 60,000 U.S. adults. We focus on the subset of more than 16,000 verified voters from the 27 states where a major-party Senate incumbent faced a challenger from the other major party.

Each respondent was asked whether they favored or opposed the confirmations of both Gorsuch and Kavanaugh. We compared these responses to the confirmation votes cast by the respondent’s incumbent senator to create a measure indicating whether the respondent agreed with zero, one or two of the incumbent’s votes. We then used this measure in analyses of respondents’ reported Senate votes.

Senators from both parties are punished for being out of step

Our general finding is that the more people disagree with the way their senator voted on these Supreme Court confirmations, the less likely they are to vote for that senator. This holds even when we account for whether the voter and the senator share the same party or ideological leanings.

We also found that congruence with a senator’s confirmation votes matters more to certain people. Those who are particularly knowledgeable about politics are most likely to use these court considerations when casting their ballots. For these more informed voters, the probability of supporting the incumbent can actually drop below 50 percent as disagreement with the senator’s confirmation votes increases.

Republican voters also appear to give more weight to a senator’s confirmation votes. This pattern is evident not just in our study of the 2018 election, but also in the other two studies that we conducted. These findings are consistent with work showing that ideology is more central to the Republican Party.

So what does this mean going forward?

Altogether, our work suggests that for those Republicans locked in competitive races, the timing of this confirmation fight may create some difficult choices. Susan Collins (R-Maine), who is fighting to win a fifth term in a state that has backed the Democratic candidate in every presidential election since 1992, has already declared that she will oppose any nominee brought up for vote before Election Day. But other vulnerable Republicans such as Martha McSally (Ariz.) and Thom Tillis (N.C.) have said they have support for a swift vote on Trump’s nominee.

Just how these different tactics will affect their respective races is difficult to predict. Our work suggests that confirming Barrett might help secure support from waffling Republicans who value the conservatism of the pick.

But partisanship and ideology are not everything. In our 2018 sample, about one-third of voters who were represented by a senator from the same party disagreed with at least one of that senator’s confirmation votes. Similarly, almost 30 percent voters who are represented by a senator from the other party agreed with at least one of that senator’s confirmation votes. This suggests that people’s opinions of Barrett’s confirmation may also be shaped by her personal characteristics as well as background that upcoming hearings will reveal.

And as the polling data referenced above indicates, voters may be split on whether the process itself is appropriate. Voting on Barrett before Election Day will require a faster-than-average vetting period and would apparently ignore the reasoning Republicans offered in 2016 for refusing to consider President Barack Obama’s nomination of Merrick Garland to replace Antonin Scalia on the Supreme Court.

The fates of Republicans fighting to hold on to their seats may be tied to whether their positions align with those of their voters. Our studies suggest that as long as Supreme Court confirmations remain a salient and contentious topic, senators in 2020 and beyond risk paying a price for ignoring the public’s opinions of the nominees.

Elizabeth Simas (@beth_simas) is an associate professor of political science at the University of Houston.

Alex Badas (@BadasTweets) is an assistant professor of political science at the University of Houston.