J.D. Vance is Trump's bold choice for VP, but can he win?

Donald Trump has put a youthful, loyal gladiator for his Make America Great Again movement on the Republican ticket, hoping J.D. Vance's transformation from blue-collar Rust Belter to senator can help him secure victory.

A White House candidate often chooses a vice presidential running mate who can appeal to new categories of voters or compensate for acknowledged weaknesses in terms of image or policy.

Trump, though, tapped a conservative white man like himself, from a state he already had every chance of winning.

"We're ecstatic," Alex Triantafilou, chairman of the Ohio Republican Party, said on the Republican National Convention floor minutes after Vance was announced as Trump's VP choice, calling him a "great addition" to the ticket.

Vance has "lived that experience" shared by millions of working-class and middle-class Americans, he said.

But will Trump's plan work?

- Age rebalance -

Even if his octogenarian rival Joe Biden appears to be suffering more than him from advanced age, Trump knows he is no spring chicken at 78.

By picking Vance, who at 39 is barely half Trump's age -- and the first millennial on a major US party presidential ticket -- he could neutralize what had been the relatively youthful advantage of Biden's vice president, 59-year-old Kamala Harris.

Should the current Democratic president bow out of the campaign, as some in his party are calling on him to do, attention might shift to Trump's age. A particularly youthful running mate would rebalance the average age on the GOP ticket.

Trump may also be looking for a capable young successor to carry the torch of Trumpism forward -- and no doubt he believes Vance has the potential to lead a new MAGA generation.

- MAGA loyalist -

Vance was once a fierce Trump antagonist, but he has made a U-turn to establish himself as one of the billionaire's most ardent defenders.

He has deleted earlier tweets critical of Trump and instead passionately embraced his ideas, advocating a radical anti-immigration fight and uncompromising economic protectionism.

And he proved his loyalty by defending tooth and nail Trump's unfounded theory that the 2020 election was stolen.

Trump was scalded by his experience with his vice president in his first term, Mike Pence, who, after years of unwavering loyalty, had declined on January 6, 2021, to comply when Trump asked him to refuse to certify Biden's election victory.

"Trump picked J.D. Vance as his running mate because he will do what Mike Pence wouldn't on January 6: bend over backwards to enable Trump and his extreme MAGA agenda, even if it means breaking the law, and certainly no matter the harm to the American people," said Biden campaign manager Jen O'Malley Dillon.

- Seduction of the Rust Belt -

Ohio has steadily shifted rightward, and Trump would theoretically carry his running mate's home state without him.

But he is betting Vance can help him win the neighboring states of Michigan and Pennsylvania, along with Wisconsin.

All three of them are crucial battlegrounds capable of tipping the scales on November 5.

Vance's 2016 memoir "Hillbilly Elegy" was extolled by some as a window into the lives and troubles of the white working class -- and their support for Trump.

Vance "embodies Pennsylvania and Michigan and Wisconsin, those Midwest states," Ohio delegate Charlie Frye, 53, told AFP at the convention.

The senator "had a blue-collar upbringing in the Midwest, which I think is really powerful."

It is notable that Trump is not thinking only of the presidential election.

Ohio is the scene of a hotly contested battle for the state's other senate seat, held by a Democrat, and Vance's momentum could aid the Republican challenger -- and in the process help the party regain control of the upper chamber of Congress.