Donald Trump has picked Senator JD Vance of Ohio, a once-fierce critic turned loyal ally, as his Republican running mate.

Trump unveiled his pick on his Truth Social social media network on Monday as supporters gathered in Milwaukee, Wisconsin, for the Republican National Convention (RNC), an extravaganza turbocharged by the attempted assassination of the former president two days earlier.

“After lengthy deliberation and thought, and considering the tremendous talents of many others, I have decided that the person best suited to assume the position of Vice President of the United States is Senator J.D. Vance of the Great State of Ohio,” Trump wrote.

A venture capitalist, Vance, 39, graduated from Yale Law School and served in the US military during the Iraq War before being elected to represent Ohio in the Senate.

He will represent a younger generation in the November 5 presidential election, which features Trump, 78, and President Joe Biden, 81, who is running on the Democratic Party ticket with Vice President Kamala Harris, 59.

From Trump critic to ‘surrogate on campaign trail’

Vance is a staunch conservative from a Republican state, but he was once a fierce Trump critic.

Reporting from the RNC in Milwaukee, Al Jazeera’s Patty Culhane said that changed in 2021 when Vance was running for an open Senate seat and he told Fox News that he had been wrong about Trump.

“He got a late-minute endorsement from Trump right before the primary campaign for that Senate seat and won. It was a very close race, a very expensive race,” Culhane said.

She added that since then, Vance has become “very close” to Trump and “a surrogate for him on the campaign trail”.

The former venture capitalist has served as a bridge between Trump associates and wealthy Silicon Valley donors, many of whom have opened their wallets to Trump this election.

Vance, who is also the author of the best-selling memoir Hillbilly Elegy, has embraced “culture war” issues, which has made him a conservative darling, particularly among Trump’s Make America Great Again base.

He regularly denounces diversity, equity and inclusion programmes, which aim to address systemic racism and other forms of discrimination.

Moreover, he has delighted Trump supporters with his confrontational social media presence, a relative rarity in the Senate, where many lawmakers still try to maintain a sense of decorum and civility.

Several of Trump’s highest-profile backers – including former senior adviser Steve Bannon and Trump’s eldest son, Donald Trump Jr – have praised Vance for pushing the Republican Party to embrace a more hands-off foreign policy approach and for supporting trade barriers.

‘Trump’s choice for VP is loyalty’

Vance, however, is unlikely to bring many new voters into Trump’s corner and may even alienate some moderates.

Some Trump supporters had pushed him to select a woman or person of colour as his vice president to expand a coalition that skews towards white men.

In selecting Vance, Trump has passed over other possible contenders, including US Senators Marco Rubio and Tim Scott and North Dakota Governor Doug Burgum.

A key factor in choosing a running mate has been where the person is from. Vance is from a state that was once considered a toss-up battleground state that was crucial to determining the outcome of presidential elections, but Ohio voted solidly for Trump in 2016 and 2020.

Steve Clemons, the host of Al Jazeera’s The Bottom Line, identified the top consideration for Trump in choosing his vice president.

“Number one above everything else is loyalty,” Clemons said.