The Republican primary for the U.S. Senate is a battle between old-guard Republicans and Donald Trump, who will be the party’s presidential nominee for the third consecutive time, and his many supporters.

The old guard, led by Gov. Mike DeWine and former U.S. Sen. Rob Portman, support state Sen. Matt Dolan. Dolan has given $10 million of his personal wealth to his campaign and has struggled to raise money from donors.

Trump and his supporters have endorsed Bernie Moreno, a former luxury car dealer and blockchain business owner. Moreno has given $4.2 million out of his pocket to his campaign and raised considerably more from donors than Dolan.

Ohio Secretary of State Frank LaRose, the other Republican in the U.S. Senate race, was initially seen as a strong candidate, but his campaign lags as we approach Tuesday’s primary.

If he loses this primary, LaRose will have experienced probably the worst year of any sitting statewide officeholder in more than 15 years. LaRose was the lead on the failed effort last August to make it harder to pass constitutional amendments and then one of the primary backers against the successful pro-abortion constitutional amendment in November.

In 2022, Dolan ran in a seven-person Republican primary and despite largely bankrolling his campaign, he finished third. Moreno was a candidate in that race but withdrew right after the filing deadline.

The winner of that Senate primary and then the general election two years ago was J.D. Vance, who was helped significantly by Trump’s endorsement.

Vance endorsed Moreno in May 2023, but it wasn’t until Trump backed Moreno in December that his campaign showed life. Trump’s support led several national Republicans to endorse Moreno and made it appear he would emerge from Tuesday’s primary to face incumbent U.S. Sen. Sherrod Brown, D-Cleveland.

Despite Trump’s endorsement, Moreno isn’t the clear front-runner with polls showing many Republicans remain undecided only days before the primary.

Ohio is likely to have this year’s most hotly contested and expensive U.S. Senate races in the nation.

Dolan received the backing of Portman last Friday and then DeWine on Monday.

Portman, who served 12 years in the Senate and was succeeded by Vance, probably doesn’t have much influence anymore among Republicans in Ohio.

When he was the sitting senator, he campaigned for Jane Timken, a former Ohio Republican Party chairwoman, for the Senate seat during the 2022 GOP primary. Timken finished a distant fifth in that race.

Dolan said of Portman: “All three of us were asking for the endorsement. It is a significant endorsement.”

The DeWine endorsement came as a surprise as he had told me in January, and other journalists in February, that he had no intention of backing any of the three candidates in the primary.

DeWine’s decision sets up a showdown with Trump. The two have an uneasy relationship. With DeWine finishing his political career when he’s done as governor, he probably doesn’t care though he won’t admit it.

Moreno’s response to the endorsements was to call DeWine and Portman “leaders of the America-last establishment wing of the GOP” and say his race is “a contest between the America-first Republican Party and the broken down RINO establishment.” RINO is Republican in name only, which is what Moreno considers Dolan.

Dolan has criticized Trump’s “personality” and “political style” as well as how he handled his 2020 defeat and the subsequent Jan. 6, 2021, attack on the Capitol.

But Dolan praises Trump’s policies and recognizes his popularity among Ohio Republicans.

Should Dolan win the primary, Trump likely will not support him.

When I asked Dolan about Trump’s endorsement of Moreno, he avoided the question. Instead, he said he’s the only candidate in this election who’s implemented Trump’s policies.

With Dolan grabbing media attention, it was announced a few hours after DeWine’s endorsement decision that Trump was coming to the Dayton area Saturday, three days before the primary, to rally for Moreno.

Also, national Democrats apparently see Moreno as the weakest candidate as they are spending about $2.7 million to prop him up.

Katie Smith, an Ohio Democratic Party spokesperson, said: “The Republicans in this race have been more focused on fighting each other than fighting for Ohioans. No matter which untested rich guy makes it through this expensive slugfest, they’ll enter the general election damaged with substantial baggage.”

Have an interesting story? Contact David Skolnick by email at dskolnick@vindy.com.