“Hillbilly Elegy” author JD Vance won Ohio’s contentious and hyper-competitive GOP Senate primary on Tuesday, buoyed by Donald Trump’s endorsement in a race that was an early test of the former president’s hold on his party as the midterm season kicks into high gear.

A onetime staunch critic of Trump whose 2016 memoir about his Appalachian childhood lifted him to fame, Vance spent much of the campaign behind in the polls. But a late-stage endorsement from Trump pushed him to frontrunner status and the two men downplayed Vance’s past scathing criticism of the former president, with Vance saying he was wrong.

In accepting the GOP nomination, Vance struck a unifying tone, complimenting his rivals — including silencing boos for his most bitter opponent, former state Treasurer Josh Mandel — and pledging to appeal to the state’s many moderates headed into November after an exceptionally bitter campaign that, at one point, saw two candidates nearly come to blows on a debate stage

“Now this campaign, I really think, was a referendum on what kind of a Republican Party we want, and what kind of a country we want,” Vance told the crowd.

Tuesday’s contests ushered in a more competitive phase of the midterm primary season, with closely watched races in Pennsylvania, North Carolina and Georgia scheduled for later this month. The election will culminate in November, when control of Congress, governor’s mansions and key elections offices are at stake.

Vance will face Democrat Tim Ryan in the general election race to fill the seat being vacated by retiring Republican Sen. Rob Portman. The 10-term Democratic congressman, who easily won his three-way primary Tuesday night, will likely have an uphill climb in a state Trump won twice by an 8-point margin. In a potential warning sign for Ryan, roughly twice as many Republicans participated in the primary than Democrats.

President Joe Biden called Ryan late Tuesday to congratulate him on becoming the nominee, and Trump was also in touch with Vance.

Meanwhile, Ohio’s Republican Gov. Mike DeWine secured his party’s nomination for a second term and will take on Democrat Nan Whaley.

In neighboring Indiana, incumbent Republicans in the state House fended off primary challengers who wanted to push the Legislature further to the right. Among the roughly two dozen so-called liberty candidates in Republican legislative races, one defeated a 10-term incumbent in northern Indiana, while a leader of the movement lost his primary race.

The campaign is intensifying at a volatile moment in the nation’s politics. On the eve of this week’s primaries, a draft U.S. Supreme Court opinion was leaked that suggests the court could overturn the 1973 landmark Roe v. Wade decision that legalized abortion nationwide. While the Democrats decried the draft, they suddenly have a clear, unifying message they hope will offset an otherwise difficult political climate dominated by economic woes that include high inflation and gas prices.

Trump, meanwhile, is using the primaries to build his reputation as a GOP kingmaker as he mulls another presidential run a year after leaving office under the cloud of two impeachments and the Jan. 6, 2021, Capitol insurrection. A Trump spokesperson Tuesday took credit for the outcome in the Ohio Senate contest, saying the former president’s endorsement “propelled (Vance) into a commanding first place finish.”

While Vance is the GOP primary’s undisputed winner, driving up support in Ohio’s rural regions, there was notable support for Mandel and state Sen. Matt Dolan, the only major candidate who did not aggressively court Trump. His traction suggests there remains appetite in the party for non-Trump alternatives, especially in a state with a long history of electing moderates, including DeWine, Portman and former Ohio governor-turned-Trump critic John Kasich.

Dolan notched strong performances in Ohio’s metropolitan communities, particularly around Cleveland and Columbus. Mandel, meanwhile, also found some rural support.

At the Strongsville library in suburban Cleveland, Joanne Mondak, 71, said she voted for Dolan because the rest of the candidates are “nutcakes” who are “too much Trump.”

Ohio, once a bellwether state, is now decidedly Republican, posing a challenge for Ryan, who has distanced himself from the progressive wing of his party during the race. Campaigning in sweatshirts and baseball caps, he has fashioned himself as a blue-collar crusader fighting for working families.

During his acceptance speech, Ryan grew emotional as he spoke about the community his steelworker grandfather was able to build while holding a well-paying union job.

“I am absolutely in my bones certain that we can do this if we come together, and it’s not about finding our differences. It’s not about hate,” he said.

Buoyed by historical trends and Biden’s deep unpopularity, Republicans are optimistic about retaking the House and Senate come November. A new president’s party almost always loses in seats in subsequent midterm elections and Republicans hope soaring inflation, high energy prices and lingering frustrations over the country’s handling of the COVID-19 pandemic will further boost their prospects.

Democrats, meanwhile, are banking the GOP — with Trump’s help — will elect candidates so extreme they prove unelectable come November. Vance, in particular, has drawn fire for dismissing Russia’s invasion of Ukraine as none of the United States’ business and accusing Biden of trying to intentionally kill Trump voters by allowing illegal drugs to cross the southern border.

“By all rights, history tells us that the Democrats are going to lose control of the House,” said Dale Butland, a Democratic strategist in Ohio. “By all rights, we should lose control of the Senate, too. However, the only thing that could save us is if the Republicans nominate a bunch of far-right crazies that are unacceptable in a general election.”

While DeWine is widely known in Ohio after a 40-year political career, he faced fierce backlash from conservatives over the COVID-19 shutdowns and mandates he imposed during the early months of the pandemic.

DeWine’s three opponents — former U.S. Rep. Jim Renacci, former state Rep. Ron Hood and farmer Joe Blystone — all tapped into that anger, but appear to have split the far-right vote. Still, DeWine didn’t take any chances and poured millions into advertising during the race’s final weeks.

On the Democratic side, Whaley became the first woman in state history to receive a major party’s backing. She defeated former Cincinnati Mayor John Cranley in a race that drew relatively little attention as much of the state focused on the contentious Senate Republican primary and the ongoing redistricting legal battle. Whaley had the support of the state’s top Democrat, U.S. Sen. Sherrod Brown, a popular household name, while Cranley had the backing of feminist icon Gloria Steinem.

The two candidates saw eye-to-eye on most major issues — guns, abortion rights, social justice — but Whaley had repeatedly pointed out that Cranley only recently said he was pro-choice.

Trump-backed Secretary of State Frank LaRose also won his party’s nomination for another term.

In the House, Republican Max Miller, a former Trump campaign and White House aide, won the GOP nomination in the sprawling new 7th District in northeast Ohio, despite allegations from his ex-girlfriend, former White House press secretary Stephanie Grisham, that he grew violent with her as their relationship deteriorated. He has denied the charges.

Miller was initially recruited to challenge Republican Rep. Anthony Gonzalez, one of the 10 House Republicans who voted in favor of Trump’s impeachment. But Gonzalez chose to retire instead.