If Biggs wins her race in South Carolina’s 3rd, that will be notable not only because the Trump endorsee would lose, but because the GOP has been slow to nominate women for safe Republican seats. Earlier in the cycle, in North Carolina’s 13th (a safe red seat), Kelly Daughtry was a contender, where she was set to face off against Brad Knott in a runoff. However, Trump endorsed Knott ahead of the runoff, and she dropped out.

—Meredith Conroy, 538 contributor

The AP reports that about 82 percent of the expected vote has reported from the GOP primary runoff in South Carolina's 3rd District, and Biggs's lead over Burns now stands at around 4 points, 52 percent to 48 percent. Looking at the results from the South Carolina Election Commission, Burns has not gotten the boost from the Election Day vote that we expected. In fact, Biggs leads among votes cast on election day, 53 percent to 47 percent, and that group of votes looks set to make up close to 80 percent of the final overall vote total. (Biggs leads 51 percent to 49 percent among the smaller number of early and absentee votes.)

—Geoffrey Skelley, 538

Utah 2nd District Rep. Celeste Maloy is the last moderate incumbent in Utah who has drawn a right-wing challenger, and she may be in slightly more danger than the others. Not only did she lose the state party's endorsement at its April convention, but she only narrowly won the Republican nomination for this seat in a 2023 special election with 39 percent of the vote. Her opponent this time around, Army veteran Colby Jenkins, has also raised a credible $379,000, and tea party-aligned outside groups have spent $534,000 to support him. But while Jenkins has the influential support of Lee, Trump's last-minute endorsement of Maloy may have halted Jenkins's momentum.

—Nathaniel Rakich, 538

We're also keeping an eye tonight on a few mild-mannered Republican incumbents who are probably safe for reelection but have displeased the GOP's right flank enough to earn a primary challenge.

For example, hardline state Rep. Phil Lyman won the state GOP's official endorsement for governor over incumbent Gov. Spencer Cox at an April party convention, but a HarrisX/Deseret News/University of Utah poll earlier this month showed Cox leading Lyman 71 percent to 29 percent among the broader primary electorate. (Republican conventions in Utah, which are largely attended by dogmatic party activists, tend to be more conservative in their tastes than voters.)

Similarly, in the 1st District, electrician Paul Miller defeated Rep. Blake Moore at the party convention and could tap into some level of discontent with Moore's moderate voting record, but he's raised all of $4,706 for the cycle, so he's unlikely to actually defeat the incumbent.

—Nathaniel Rakich, 538

Tonight, we'll be monitoring how candidates of color perform in primaries for Senate, House and governor. Overall, 19 people of color — 12 Democrats and seven Republicans — are running in these contests, all for the House.

Each state has a candidate of color running in at least one race, but New York, which also has the most contests overall, is home to 10 of these candidates, including former Rep. Mondaire Jones, who is running in the 17th Congressional District. He tried to switch districts in 2022 due to redistricting and lost the primary in the 10th District, but this year he is running unopposed and hoping to unseat Republican Rep. Mike Lawler.

In Colorado, Democratic incumbent Rep. Joe Neguse is running unopposed in the primary for the state's 2nd Congressional District. In the 3rd District, Stephen Varela, who sits on the state's Board of Education, is the only person of color among six candidates hoping to take on Democrat Adam Frisch for the seat left open by Boebert running in the 4th District this cycle. Asian American Peter Yu, a finance and mortgage consultant, is one of her five challengers in that district. In the 8th Congressional District, are vying to take on the incumbent Democrat, Rep. Yadira Caraveo, a seat Republicans hope to flip in what could be a close race.

Finally, there are currently only four Black Republicans in the House, but Burns could add to that number if he wins his runoff in South Carolina (he is slightly favored against Biggs). Meanwhile, one of those four incumbents, Rep. Burgess Owens, is unopposed in Utah's 4th District.

—Monica Potts, 538