VANDALIA, Ohio — President Donald Trump rallied Saturday for Republicans in Ohio’s competitive races for Senate and governor, predicting that the party will defy expectations in a choppy midterm election climate.

“I think we’re going to have a big surprise, because they don’t know what’s happening,” Trump said while speaking onstage inside a high school gymnasium near Dayton.

“Just get out and vote,” Trump added. “If you do that, we’re going to win, and we’re going to win big. And we’re going to shove it up their ass.”

The visit, part of what White House officials have told NBC News will be a push through at least 17 states between now and Nov. 3, was aimed at boosting incumbent Sen. Jon Husted and Vivek Ramaswamy, the GOP nominee for governor.

Trump, who won Ohio three times by comfortable margins, opened his speech with praise for both before moving into broader remarks to promote himself and his administration. He also offered support for local Rep. Mike Turner and for several House candidates in attendance, including Derek Merrin, the Republican running against longtime Democratic Rep. Marcy Kaptur in northwest Ohio.

Husted’s bid to keep the Senate seat — which he was appointed to after JD Vance was elected vice president — has in particular become a subject of concern among Republicans in Ohio and Washington. In August, the National Republican Senatorial Committee warned in a memo that Husted’s past enthusiasm for building data centers was hurting his campaign. Others have expressed worries that Husted, who has long wanted to be governor, has not put his full heart into the race.

The battle is one of the most expensive and competitive Senate races in the country this fall. Along with a handful of other key contests, the clash between Husted and Brown could determine partisan control of the chamber. This week, Senate Leadership Fund, a super PAC affiliated with Senate Majority Leader John Thune of South Dakota, poured another $14 million into Ohio to prop up Husted, bringing the group’s investment in the state to $93 million.

“Senator Jon Husted votes to put Ohio first, and he votes all the time,” Trump said before relating conversations he’s had with Thune and others: “They think he’s phenomenal.”

The high school gym where Trump spoke Saturday night was a smaller venue than has been typical for his rallies. The home court of the Butler High School Aviators seats up to 5,000. There were several stretches of empty seats in upper bleachers as Trump took the stage — and many more by the time he finished speaking 93 minutes later.

In Ohio and elsewhere, Republicans are wrestling with how to win at a time when polls show Trump and the war in Iran are highly unpopular and when voters most loyal to Trump might stay home because he’s not on the ballot.

“As a lifelong Republican who’s voted in every election since I was 18 and in every primary election as a Republican, I have real concerns that we’re going to be able to turn out the every-four-year Trump voter,” Nick Owens, a former GOP chair in Ohio’s Brown County and former member of the state Board of Education, told NBC News last month. “I have real concerns that those voters just will not come to the polls.”

Trump acknowledged that dynamic explicitly Saturday and repeated an argument he’s been making on the campaign trail this fall.

“When I run, we win,” Trump said. “But for some reason, when I don’t run, they draw 44% less people. So what I’m going to do is ask you to just pretend that I’m running, because if we do, and if you draw the people, you’re going to win, and we’re going to win big.”

Husted, speaking to reporters before the rally, described Trump as a unique asset in his race.

“Well, he won Ohio by 11 points in the last election, and if we get those same voters to turn out in this election, we’ll win,” Husted said.

Alex Triantafilou, the Ohio GOP chair, told NBC News that the rally was “hugely important” in the effort to motivate those low-propensity, Trump-loyal voters.

“We know in Ohio that if we turn out the same electorate that we turned out in 2024, that we’ll win every race,” Triantafilou said in an interview. “Nobody speaks to that crowd better than President Trump.”

The Saturday rally included a cameo from Jon Gruden, the former NFL coach who years ago was a teammate of Husted’s on the University of Dayton football team.

“Jon Husted is a lot more than my friend,” an animated Gruden told the audience. “He was a great player. … He will never quit on you or anybody.”

Trump marveled about Husted’s football-playing days, of which he said he was unaware until hearing about them from Gruden.

“Nobody told me you were a great athlete,” Trump said, before taking a jab at his Democratic rival: “And Brown was not — he was not an athlete. That guy can’t tie his shoes.”

For its part Saturday, the Brown team sent a mobile billboard linking Husted’s support for the war in Iran to higher gas prices through Dayton and on the streets near the rally.

“Jon Husted has turned his back on working families — he’s only looking out for his billionaire buddies and special interests,” Brown said in a statement from his campaign.

Ohio also is home to what polls show is a close race to succeed term-limited Republican Gov. Mike DeWine. Ramaswamy faces Democrat Amy Acton, a physician who served as the state’s health director under DeWine. Ohioans have not elected a Democrat as governor in 20 years, but at a time when high prices rate as a top-of-mind concern for voters, there are questions about the billionaire Ramaswamy’s appeal, especially in the rural parts of the state.

Ramaswamy, like Husted, addressed the crowd early during the rally, and Trump invited both to return to the stage during his speech for additional remarks. Trump introduced Ramaswamy by noting how he had briefly run against him for the 2024 Republican presidential nomination.

“He was a nasty guy,” Trump said of Ramaswamy. “But you know what? He was smart. He loves the state. He’s actually got a great heart.”

Compared with Husted, Ramaswamy was otherwise less of a focus of Trump’s remarks. Trump, for example, criticized Senate Democrats who this week blocked Husted’s Ratepayer Protection Act, which aims to rein in higher utility costs associated with power-hungry data centers.

Republicans, Trump said, are “taking historic action to ensure that Big Tech data centers benefit local communities.”

Trump then made the argument for data centers, despite the fears it could be a losing issue for Husted.

“We want them,” Trump said. “Look, there’s so much money to be made for Ohio. You can’t just turn them off. They’ll go to China.”

Trump also recited the lyrics to the 1968 Al Wilson song “The Snake” — a recurring, crowd-pleasing bit in his rally speeches — with a new, localized twist. Trump dedicated the song, which he uses as an allegory to trusting communities that welcome immigrants, to nearby Springfield, Ohio.

The city became a flashpoint in the 2024 presidential election after Trump repeated the unsubstantiated and racially charged claim that Haitian immigrants in the city were eating dogs and pets.

At another point, the crowd broke into chants of “four more years” for the term-limited president.

“I’d love to do the four-more-year thing,” Trump responded in a teasing tone before suggesting that the press would overplay his remarks.

“We’re driving them totally crazy,” Trump said, referring to the media. “But I love doing it. I love being with you. I really do.”