Donald Trump arrives in Ohio today to campaign for Senate candidate Bernie Moreno

Former President Donald Trump will arrive in Ohio today to campaign for his preferred U.S. Senate candidate ahead of Tuesday's primary.

Trump is scheduled to speak at 4 p.m. at a rally for businessman Bernie Moreno, who is running for the chance to take on Democratic Sen. Sherrod Brown this fall. The event at the Dayton International Airport was organized by Buckeye Values PAC, an outside group supporting Moreno's campaign.

VOTERS GUIDE: What you need to know about the March 19 election

Doors open at noon.

Moreno is running in the Republican primary against Secretary of State Frank LaRose and state Sen. Matt Dolan, R-Chagrin Falls. Trump endorsed Moreno back in December, which many observers thought would make Moreno the clear frontrunner. Instead, he and Dolan are locked in a tight battle as the race nears its end − with many Republicans still unsure who to support.

"Look at how much money is going to be spent over the next eight days," Moreno told supporters in Columbus earlier this week. "It's going to be all negative ads attacking me because they know that I'm a threat to their system. This is the last vestiges of the Bush, Cheney, Kasich Republican Party. We need to make certain that stops."

Ohio Senate race heats up as Trump visits Ohio

The former president's visit adds gasoline to a primary contest that's heated up in recent weeks.

Independent polling has been limited, but twosurveys released this week showed Moreno and Dolan fighting for the lead with a plurality of voters undecided. While LaRose boasts the highest name recognition, his campaign appears to be languishing as Dolan enjoys late momentum. Dolan also secured key endorsements from Gov. Mike DeWine and former Sen. Rob Portman.

Meanwhile, the campaigns and outside groups have spent millions in advertising over the past week alone − another sign the race is close.

"If that person supports Trump because that person liked the policies that were put in place − that we were stronger in the world, that we had less taxes, that we had a secure border − then look at me because these are a lot of the things I was able to accomplish in my time in Ohio," Dolan told reporters Wednesday.

Trump himself is on the March 19 ballot, but Ohio won't have much of a role to play in the presidential primary. He and President Joe Biden are set for a rematch in November now that they've won enough delegates to secure their parties' nomination.

Still, Trump can use today's visit to energize supporters in a state he won by 8 points in 2016 and 2020. He also brags about the power of his endorsements, meaning he has a personal interest in getting Moreno over the finish line.

This story will be updated.

Haley BeMiller is a reporter for the USA TODAY Network Ohio Bureau, which serves the Columbus Dispatch, Cincinnati Enquirer, Akron Beacon Journal and 18 other affiliated news organizations across Ohio.

This article originally appeared on Cincinnati Enquirer: Donald Trump rallies in Ohio for Senate candidate Bernie Moreno