Republican senate candidate JD Vance and Donald Trump Jr. host an event ahead of next month's primary election in Independence, Ohio, U.S., April 20, 2022.
Republican senate candidate JD Vance and Donald Trump Jr. host an event ahead of next month's primary election in Independence, Ohio, U.S., April 20, 2022. Reuters / GAELEN MORSE

Democratic U.S. Representative Tim Ryan will take on the winner of a hotly contested Republican primary for a U.S. Senate seat in Ohio that offers an early test of Donald Trump's influence over his party as he considers running for the presidency again in 2024.

Ryan, who ran a brief 2020 presidential campaign, won his Senate primary as had been expected, Edison Research projected less than an hour after the polls closed.

Former president Trump upended the Republican Senate primary last month by endorsing author and venture capitalist J.D. Vance, 37, ahead of November congressional elections.

Opinion polls show Vance, author of the national bestseller "Hillbilly Elegy," opening up a narrow lead since Trump's endorsement over his nearest rivals, state lawmaker Matt Dolan and former state Treasurer Josh Mandel.

In a Sunday evening rally, Trump appeared to confuse two of the candidates' names, telling the crowd that he backed "J.D. Mandel" to take the seat of retiring Senator Rob Portman.

"This is a test of his ability to anoint someone," said University of Cincinnati political science professor David Niven. "The endorsement has made this Vance's race to lose."

Outside a polling place at the Ronald Reagan Lodge in West Chester on Tuesday, Ohio voter Raymond Reynolds said he had cast a ballot for Vance largely on Trump's word.

"He's made some statements he shouldn't have made, but Donald Trump endorsed him, and he probably knows more about him than I do," Reynolds said.

Another Trump supporter, Thomas Cheesman, however, said he voted for Dolan despite Trump's endorsement of Vance.

"I had somebody else in mind before that, and I stuck with that choice," he said. "He didn't sway me."

Nonpartisan election analysts favor Republicans' chances of winning the final Nov. 8 matchup.

The governorship and a rematch between two Democratic rivals for a U.S. House seat are also on the ballot in Ohio on Tuesday, while voters in Indiana will also cast primary ballots.

Tuesday's contests kick off a series of critical nominating contests in the coming weeks, including primaries in North Carolina, Pennsylvania and Georgia.

Trump has endorsed more than 150 candidates this year, including about a dozen key picks.

His involvement will help determine whether Republicans, as expected, reverse their slim deficit in the House and also possibly take control of the Senate, which is split 50-50 with Democrats owning the tie-breaking vote.

A loss of control of either chamber would allow Republicans to block Democratic President Joe Biden's legislative agenda and also to pepper his administration with distracting and potentially politically damaging investigations.

Trump has not announced his plans for 2024, but he regularly hints at his political rallies that he intends to mount another presidential campaign.

REPUBLICAN PUSHBACK

Not all party members are falling in line behind Trump's lead. As in Ohio, Trump-backed candidates for U.S. Senate in Pennsylvania and North Carolina face well-funded Republican challengers.

Some worry that Trump's picks, like former football star Herschel Walker in Georgia, could prove too controversial to prevail against Democrats in November, imperiling their bid for Senate control.

Vance, a former Trump critic, was not the choice of many party leaders in Ohio, and some have grumbled publicly about Trump's decision. The Club for Growth, a powerful conservative advocacy group, has broadcast ads bashing Vance and is sticking by its pick in the race, the unabashedly pro-Trump Mandel.

Miranda Yaver, a political science professor at Oberlin College, said a Vance loss would not necessarily point to the end of Trump's iron grip hold over the party, given that four of the five Republican candidates lobbied for Trump's endorsement.

"I don't think it's a real loss for the Trump agenda if Vance loses because it's still going to be an 'America First' candidate," Yaver said. "There are (other) people in this race that are more ideologically aligned with Trump."

The Democratic primary between progressive candidate Nina Turner and incumbent Shontel Brown for the congressional district which includes Cleveland will be closely watched as a measure of the power balance between the establishment and more liberal wings of the party.

In the Republican primary for governor, incumbent Mike DeWine held off challenges by three far-right Republican challengers who are splitting the anti-DeWine vote. Trump did not endorse anyone in the race.

In Indiana, the contest for a congressional district in a historically Democratic stronghold outside Chicago has earned some attention, with seven Republicans vying for the chance to oust freshman Democratic Representative Frank Mrvan in a race seen as potentially competitive in November.