AMNA NAWAZ: One of the nation's most closely watched Senate races this year is now set.

Ohio businessman Bernie Moreno cruised to victory in the state's U.S. Republican Senate primary last night, after earning the backing of former President Donald Trump.

He will take on incumbent Democratic Senator Sherrod Brown this fall in a race that will help decide control of the Senate.

Following it and other elections in the state is Ohio Statehouse News bureau chief Karen Kasler.

Karen, always good to see you.

So these results last night with this Cleveland-based businessman Bernie Moreno backed by Mr. Trump beating out the other two candidates, was this the expected outcome?

KAREN KASLER, Ohio Public Radio and Television: I think so.

And it really came down to two things, and both of them involve former President Trump.

It came down to Trump's endorsement, and also about $2.5 million, $2.7 million worth of ads that were purchased by a political action committee that's connected to U.S. Senate Democrats.

They had put ads out trying to portray Moreno as too conservative for Ohio, because he had been endorsed by Trump.

And Democrats said, it seemed to be, that they wanted Moreno to be the candidate who runs against Democratic incumbent Sherrod Brown.

Republicans call that meddling in the election.

And it turned out potentially that that, along with a Trump rally at the airport in Dayton on Saturday, those two things may have been the two things that really vaulted Moreno over and had him win by a little over 17 percentage points.

AMNA NAWAZ: Well, we should point out this is in a state that Mr. Trump won by eight points in 2020.

I should point out Senate Majority Leader Chuck Schumer told me recently that he is not worried about the Democratic incumbent, Senator Sherrod Brown.

Should he be?

KAREN KASLER: Well, when you look at the results from election night, Bernie Moreno won in every county in Ohio, and he was facing two opponents, Secretary of State Frank LaRose and state Senator Matt Dolan.

Dolan was his real competition toward the end.

Dolan was more of a GOP establishment candidate endorsed by Governor Mike DeWine and former Senator Rob Portman.

And yet Dolan really ended behind, well behind Moreno in the final result.

So the idea that Moreno has done so well in so many counties against a more -- somebody who was perceived as a more moderate candidate, though still aligned with Trump, is interesting.

And also Moreno's strongest performance was in the Youngstown area.

And that's an area that Sherrod Brown used to have a lot of support in.

It's gone more and more Republican over time.

And so that's going to be a critical area for both those candidates.

AMNA NAWAZ: Karen, as you know, this has already been a brutal and, as you shared, a very expensive primary for Republicans so far.

It's getting a lot of national attention.

It's a top target for the GOP.

What do we expect ahead?

KAREN KASLER: I expect this to be the most expensive U.S. Senate campaign in Ohio history.

It's on track for that, $56 million already involved from the three candidates who ran for the Republican nomination and Sherrod Brown himself, who has much more money than all three of the candidates who were running for the Republican nomination have put together.

So, certainly, we're going to see it top the 2022 U.S. Senate race in Ohio, which was the most expensive race in Ohio history.

And I think there's going to be a lot of interest from not only people in Ohio, but also outside Ohio, because the Senate margin is so slim.

And Republicans really feel that this is a seat that they can knock off.

Democrats feel that Sherrod Brown speaks to not only their voters, but also can reach more moderate Republicans and voters who are independent.

So it's really going to be a battle, I think.

AMNA NAWAZ: There's another key House race I know you're following in Northwest Ohio.

There's a Trump-backed candidate there, Derek Merrin, who won his primary.

He's now going to face Congresswoman Marcy Kaptur in November.

Is this a seat that Republicans could flip?

KAREN KASLER: Well, Marcy Kaptur is the longest-serving woman in Congress, and she's been popular even after her district was redrawn to really try to make it more competitive.

Last time, she ran against a candidate, J.R. Majewski, a Trump-aligned candidate.

He ran this time, but had to drop out because of derogatory comments that he made about Special Olympians that got him in trouble.

And that whole situation as well as the other candidates in the race really seemed to benefit Derek Merrin, who himself was involved in a battle over leadership in the Ohio House.

And so his name being out there with that may have helped him come -- it may have helped win that contest, but he does have an uphill battle in facing Marcy Kaptur.

AMNA NAWAZ: A lot to follow in Ohio.

We are so glad you're here to help us with that.

That is Ohio Statehouse News bureau chief Karen Kasler.

Karen, thank you very much.

KAREN KASLER: Great to talk to you.

Thanks.