When senator JD Vance takes the stage at the Republican National Convention in Milwaukee on Wednesday, he will be viewed by many Republican Party faithful as the newly anointed inheritor of Donald Trump's Make America Great Again movement.
Mr Trump's choice of the 39-year-old Vance, a fire-breathing populist, as his vice-presidential pick signalled the former president, 78, views his MAGA movement as something that could stretch beyond his own time in power. If Mr Trump wins the November 5th presidential election, he can serve only until 2029.
Mr Vance's task on Wednesday and in ensuing months will be to reassure those dubious about his MAGA credentials of his bona fides while bringing voters sceptical of Mr Trump into the fold, having once compared Mr Trump to Adolf Hitler before his conversion to stalwart Trump defender.
Erick Erickson, a prominent conservative commentator, believes Mr Vance, who rose to national fame after writing a bestselling memoir "Hillbilly Elegy," can thread that needle.
JD Vance can speak Trump to people who don’t understand Trump.
"JD Vance can speak Trump to people who don’t understand Trump," Mr Erickson told Reuters in an interview. "He can explain his agenda."
That MAGA agenda, he said, is largely a loose form of economic populism that focuses on the middle class and favours more government involvement in the economy and seeks to avoid foreign alliances and entanglements.
The MAGA movement itself is both an exercise in media branding and an all-purpose term to define Mr Trump's diehard supporters.
They include those who nurse deep-seated racial grievances and many who follow his lead on policy matters regardless of where they fall on the ideological spectrum.
“In Trump's hands it's just instincts and impulses, some of which emerge from white grievance,” said Damon Linker, a political science lecturer at the University of Pennsylvania. “But in Vance's (formulation), it's much bigger than that. Or at least he wants it to be.”
Mr Vance, a graduate of Yale Law School and a former venture capitalist, is now well positioned to help mould Mr Trump’s often scattershot vision into something coherent for the future, he said.
Where Mr Trump often traffics in simple but memorable phrases, Mr Vance can delve deeply into policy nuances at conservative forums and in extended interviews with the media.
MAGA 'intellectual firepower'
"He does bring an intellectual firepower to whatever MAGA stands for," Mr Erickson said.
That could be crucial because Mr Trump's movement has never been ideological, but based on the instincts of Mr Trump himself, Mr Linker said. Without the right successor, it could die with him.
The question for Mr Trump's movement going forward is whether somebody with less charisma than Mr Trump, a former reality TV star, "can communicate this message in a way that’s effective," said Suzanne Schneider, a historian who studies conservatism at Oxford University.
Mr Trump's critics are doubtful and say the force of his celebrity and personality has given him influence that would be nearly impossible for a would-be successor to replicate.
Senate freshman
Elected to the US Senate less than two years ago, Mr Vance has spent much of his brief political career arguing the government needs to do more to assist the working class by advancing policies that boost wages.
Those policies, according to Mr Vance, can take the form of limiting illegal immigration, restricting imports, raising the minimum wage and cracking down on corporate largesse - positions that aren't entirely in line with Republican orthodoxy but track Mr Trump's MAGA agenda closely.
Last year, Mr Vance partnered with Democratic senator Elizabeth Warren on legislation that would penalise bank executives when their institutions fail.
Some at the convention viewed Mr Vance's selection as a sign the MAGA movement has advanced to where Mr Trump can eventually pass the baton to others.
“I see the selection of JD Vance as the continuation of Donald Trump’s policies, of America First policies,” said Chuck Hernandez, chair of the Chicago Republican Party. “We’re at the point where we needed to mature and go and continue.”
MAGA power struggle
Mr Vance isn't alone. An entire new generation of MAGA acolytes could be scrambling for power and influence when Mr Trump leaves the stage.
Potential rivals include Vivek Ramaswamy, 38, the tech entrepreneur who ran for president this year and enjoyed a spurt of popularity among Mr Trump’s base, Arkansas governor Sarah Sanders, 41, who served in the Trump White House as press secretary, and perhaps Mr Trump’s son, Donald Trump Jr, 46, who has worked steadily to make himself a behind-the-scenes kingmaker in the party and who strongly backed Mr Vance.
“There is an entire movement behind him full of people who are younger and smarter and will be better and more efficient in governing,” Ms Schneider said.
Carla Sands, a former US ambassador to Denmark and a fundraiser for Mr Trump who attended the convention as a delegate from Pennsylvania, said the MAGA movement will have legs beyond Mr Trump because of its focus on the middle class.
“The working people in our country over the last 30 years have been left behind,” Ms Sands said. “I consider them to be the forgotten men and women. And they’re forgotten no more under this movement.”
