Steady election overperformance by Democrats could signal a new electoral paradigm in which Republicans will need to get unmotivated voters out to the polls if they want to win in November.

In a special election Tuesday night, a former Air Force officer running on the Democratic ticket, Michael Kripchak, vastly outperformed expectations against state Senator Michael Rulli, a Republican.

In the race for Ohio’s Sixth Congressional District, Mr. Rulli won by about 10 points — a healthy margin, except for the fact that Congressman Bill Johnson, a Republican, won the district in 2022 by 29 points, signaling a 20 point swing in favor of Democrats in the last two years.

The result was another instance of consistent overperformance by Democrats in elections, a trend which began after Roe v. Wade was overturned and carried on through the 2022 midterms and into special elections this spring.

This persistent overperformance for Democrats raises questions as to why Democrats keep outdoing expectations. One potential reason is that Democrats have built a coalition of high propensity voters — those who show up to the polls as much as they can.

A survey conducted by the  National Opinion Research Center at the University of Chicago and the University of Pennsylvania found that Democrats are dominating among those who reliably show up to vote.

The survey asked respondents whether they planned to support President Biden or President Trump and sorted respondents by how many on-cycle elections they had voted in since 2018.

They found that among voters who had not voted in any election — 2018, 2020, or 2022 — Trump won the plurality of support, 44 percent to Mr. Biden’s 26 percent. However, Mr. Biden’s support increased in a direct relationship with the number of times a respondent had voted.

Among those who voted once, Mr. Biden received 33 percent support to Trump’s 45 percent support. Among those who voted twice, Mr. Biden enjoyed 43 percent support to Trump’s 41 percent support. And, among those who voted three times Mr. Biden enjoyed 50 percent support to Mr. Trump’s 39 percent support.

The associate editor of Sabato’s Crystal Ball at the University of Virginia Center for Politics, Miles Coleman, tells the Sun that “Dems doing better with the higher propensity crowd is a reversal from the Obama era.”

“Democrats had strong years when Obama was on the ballot, but his midterms, which were lower-turnout, were a struggle for Dems,” Mr. Coleman says.

Mr. Coleman added that this phenomenon was something that forecasters are “trying to price into our predictions” and that low propensity voters are “more mercurial.”

The associate director of the University of Massachusetts Lowell Center for Public Opinion, John Culverius, tells the Sun that “Anyway you slice it, people who have a more regular voting history look like they’re supporting Biden more, and to an even greater extent looking like they’re supporting Democrats more.”

According to Mr. Culverius, this phenomenon is beginning to show up in some pollsters’ likely voter models as well.

A June Big Village survey, for instance, had Trump ahead 40 percent to 39 percent among registered voters but had Mr. Biden ahead 43 percent to 42 percent among likely voters. 

Among all Americans — regardless of voter registration status — support for both candidates was even softer, with Trump leading Mr. Biden 36 percent to 34 percent.

Mr. Culverius noted that the fact that this high propensity Democratic voter trend goes back to 2018 suggests that these voters’ motivations are not just a reaction to the Roe ruling. 

Instead, it appears that Trump has minted a cohort of voters who will come out to vote against Republicans at every opportunity. He says that the low propensity voters who break for Trump also tend not to pay attention to politics.

“Those voters are disaffected and not paying close attention to the race,” Mr. Culverius says. “To me, it centers more on attention rather than propensity to vote.”

Republican operatives have also faced challenges in getting their supporters to the polls, given Trump’s claim that Democrats stole the 2020 election and his party’s embrace of this claim.

“Republicans have a very specific apathy problem in that their messaging about votes not being counted properly is actually really good at suppressing turnout,” Mr. Culverius says. “It sends the message that voting doesn’t matter at all.”

In some ways, this message is a self-fulfilling prophecy, with the clearest example being the Georgia senatorial runoffs in 2020, when Trump said the election was and would be stolen and Republican turnout suffered.

Democratic messaging around voter suppression tends to have the opposite effect, in Mr. Culverius’s assessment. “When voters hear that, they say ‘I’ll show them and go out and vote,’” Mr. Culverius says.

In the general election, this relatively new dynamic suggests that much of the GOP’s success or failure will depend on their ability to get their low propensity voters to actually cast a ballot.

Congressman Lee Zeldin, who launched the Leadership America Needs committee earlier this year, has been sounding the alarm about GOP voter turnout, saying “Republicans must do everything in their power, every minute of every day, to get out the vote.”

“We need to lean more than ever into early voting and get our low-propensity voters out in larger numbers,” Mr. Zeldin tells the Sun. “There is now a historic, grassroots effort on the right activating volunteers, poll watchers, door knockers, and phone bankers like never before.”

While Republican officials like the Republican National Committee co-chair Lara Trump say that the party is attempting to mobilize a robust get-out-the-vote effort in 2020, it’s not clear whether it will be enough to overcome the party’s leader, who is already claiming that the 2024 election will be rigged and rife with voter fraud.