Venture capitalist JD Vance’s come-from-behind victory in a <a href="https://www.thenationalnews.com/world/us-news/2022/05/03/midterms-2022-what-to-know-about-ohio-and-indiana-primaries/" target="_blank">crowded Republican primary</a> for a US Senate seat in Ohio produced another winner: former US president Donald Trump. Mr Vance, making his first bid for public office, defeated six other candidates in Tuesday’s <a href="https://www.thenationalnews.com/tags/republicans" target="_blank">Republican</a> primary contest. All but one of the leading contenders had cast themselves as standard bearers of Mr Trump’s “America First Movement”. A representative for Mr Trump on Tuesday credited the former president for Mr Vance's win, saying Mr Trump's endorsement “propelled [Mr Vance] into a commanding first place finish". Mr Trump’s influence has been on display during the primary season, with candidates mimicking his style and staking claim to his legacy. “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,” Mr Vance said in his acceptance speech. The president's endorsements will still be tested in the coming weeks with Republican primaries in Pennsylvania, North Carolina and Georgia. The Ohio primary race was one of the most expensive in the country, with candidates and the committees supporting them spending more than $72 million — mostly to attack each other, media-tracking firm AdImpact reported. Tuesday’s election took place a day after a leaked draft opinion indicated the Supreme Court was poised to <a href="https://www.thenationalnews.com/world/us-news/2022/05/04/kamala-harris-calls-us-supreme-court-threat-to-roe-v-wade-an-assault-on-freedom/" target="_blank">overturn Roe v Wade</a>, an issue that could sway suburban women voters in November’s general election and test whether Ohio has moved squarely away from being a swing state and is now solidly Republican. Mr Vance now faces US Representative Tim Ryan, who easily won the Democratic Senate primary, in the bid to replace retiring Republican Rob Portman. Mr Ryan is running a campaign focused on economic issues affecting working-class voters who left the party under Mr Trump and has already released an advertisement attacking Mr Vance’s ties to California. In his victory speech on Tuesday night at an event in Cincinnati, Mr Vance said Mr Ryan “is running as a Trump Democrat”. Mr Trump said in a “tele-town hall” call on Monday night that he endorsed Mr Vance because he’s the best candidate to defeat Mr Ryan. But dozens of Ohio Republican county chairmen, state committee members and 2016 delegates for Mr Trump urged the former president not to back Mr Vance. The former president confused the names of Mr Vance and opponent Josh Mandell when backing the <i>Hillbilly Elegy </i>author at a Sunday rally. “You know, we’ve <a href="https://www.thenationalnews.com/world/us-news/2022/04/11/trump-endorses-tv-doctor-oz-in-us-senate-race/" target="_blank">endorsed Dr Oz</a>. We’ve endorsed — JP, right? JD Mandel, and he’s doing great. They’re all doing good,” he said. Mr Vance portrayed the race as a “battle for the soul” of the party between establishment Republicans and populists like Mr Trump and himself. He even took an “America First” position that he cares more about illegal immigration and drug smuggling at the southern US border than <a href="https://www.thenationalnews.com/world/2022/02/18/russia-ukraine-latest-news/" target="_blank">Russia’s invasion of Ukraine</a>. Mr Trump’s endorsement came late, after early voting had started. But it helped Mr Vance peak at the right time and give him momentum that generated a sense that his victory was inevitable, said Mark Weaver, a veteran Republican strategist in Ohio. His other high-profile endorsed candidate in Ohio, former White House aide Max Miller, won the Republican congressional primary in the 7th District against three other candidates. <i>The Associated Press contributed to this report</i>