That’s because Kris Kobach, the former secretary of state and failed gubernatorial candidate, is one of the frontrunners heading into the August 4th contest. Kobach was the only Republican to lose a statewide election in 2018 when he ran for governor—a scenario operatives are worried will be repeated if he’s the nominee.

That fear has caused establishment Republicans, including retiring Senator Pat Roberts whose seat Kobach is hoping to replace, to throw their weight behind state representative Roger Marshall.

“Marshall gives them the best chance of keeping the seat red,” Nathaniel Birkhead, an associate professor of political science at Kansas State University, told Newsweek. In total, there are 11 candidates competing for the nomination on Tuesday.

Kansas, who hasn’t elected a Democrat to serve in the Senate since 1932, has quickly emerged as a potential battleground for majority control of the upper chamber. Democrats need to flip four or five seats in order to reclaim control, which analysts say is a possible feat amid President Donald Trump’s declining poll numbers across the country. Amid the chaotic primary, Senate Majority Leader Mitch McConnell even tried to recruit Mike Pompeo to run for the seat just weeks before the deadline but ultimately failed to convince the secretary of state to jump into the race.

Election forecasters such as Cook Political Report and Sabato’s Crystal Ball currently rate the race as “leaning Republican.” But the Cook Political Report warned that if Kobach became the nominee, the contest could move into “toss-up” territory.

While some polling earlier this year showed Marshall with the advantage, more recent surveys have round the race to be in a dead heat. A June Civiqs poll of nearly 700 registered voters found the two conservatives neck and neck, with 41 percent backing Kobach and 42 percent backing Marshall in hypothetical matchups against Democratic candidate Barbara Bollier.

The primary has only gotten more competitive as outside groups have been investing millions of dollars into the contest.

A Democrat-aligned PAC has spent at least $3.5 million in ads trying to boost Kobach by attacking Marshall. One advertisement described the state representative as “reckless and too risky for Kansas Republicans.” On the Republican side, the Senate Leadership Fund spent more than $1 million in an effort to aid Marshall’s campaign.

Newsweek has reached out to the Kobach and Marshall campaigns but did not receive a response by publication.

Trump, who has a history of waging endorsements in competitive Republican primaries, hasn’t stepped into the fray, although according to reports, many in the GOP have urged him to back Marshall.

Birkhead said it’s unusual that the president hasn’t weighed in on the race and that it may be a sign that he’s aware of his waning support in Kansas, which he won by 21 points in 2016 but is now polling just 12 points ahead of Democrat Joe Biden.

“It shows that he’s not comfortable expending political capital in this,” Birkhead said. “That indicates either a concern that he doesn’t have very much political capital and doesn’t want to look weak, or that he’s not really sure which direction he wants to go.”

Both candidates have a voting record that indicates they would stand with Trump on key issues such as immigration, abortion and health care. Kobach advised Trump on immigration policy and was picked to lead the president’s short-lived “Commission on Election Integrity,” presumably because he authored one of nation’s strictest voter-identification laws during his time as secretary of state.

A last-minute Trump endorsement could change the race. In 2018, the president announced his support for Kobach in the final days of the Republican primary for governor. Kobach ended up narrowly defeating his opponent by a few hundred votes but went on to lose the general election to Democrat Laura Kelly by five points.

Whoever wins the primary is likely to face Bollier, a physician and former Republican Kansas state senator who is seen as a lock to win the Democratic contest on Tuesday. She is backed by the Democratic Senatorial Campaign Committee and is leading the cash dash among all the candidates.

“Dr. Barbara Bollier is building a strong campaign focused on the issues Kansans care about most like access to affordable health care, she’s outraising the entire Republican field combined, and she’s well-positioned to take on whoever emerges from this very nasty and expensive primary,” Stewart Boss, a spokesman for the DSCC, told Newsweek.