By Nathan Layne, Nandita Bose and Steve Holland
DALLAS, Sept 10 (Reuters) - Vice President JD Vance takes center stage at the Republicans' Dallas convention on Thursday in a speech seen as an early test of his 2028 White House prospects, as party leaders grapple with how to sustain Donald Trump's movement amid slipping approval ratings and uncertainty over the midterms.
With Trump constitutionally barred from seeking a third term, Republicans will be watching for clues about how Vance would lead a party transformed by the president and for any sign Trump views his vice president as his preferred successor.
The unusual party meeting has been dominated by Trump's proposal on Wednesday to pay every U.S. adult a $5,000 "Trump dividend" if his party wins the November 3 congressional elections.
Trump made the extraordinary overture during a primetime speech that lasted nearly two hours and firmly placed him at the center of the midterm campaign.
Vance was scheduled to give the keynote address at 9 p.m. EDT on Thursday night (0100 GMT on Friday), though Trump was scheduled to make closing remarks to bring the made-for-television two-day event in Dallas to an end.
RUBIO AND CRUZ IN THE MIX
Vance's speech could offer the clearest indication yet of how he would seek to shape the Republican Party after Trump leaves office. Trump has been known to ask people around the White House whether they see Vance or Secretary of State Marco Rubio as the frontrunner.
Beyond Vance and Rubio, other Republicans are jockeying for position.
Senator Ted Cruz of Texas, who spoke on Thursday at the convention, told MS NOW in an interview last month that Republicans were not unified behind Vance and that the party was headed for a broader debate over its direction and priorities.
Rubio was not scheduled to speak as he was wrapping up a three-nation tour of South America.
With Trump, 80, no longer atop the ticket, many Republicans view Vance, 42, as well positioned to carry forward the party's populist, anti-establishment agenda, citing his youth and appeal to activists who now form the movement's core.
"I think he has positioned himself really well to be that kind of generational leader the party needs," Stefano Forte, president of the New York Young Republican Club, said of Vance.
The convention's focus on Trump – some Republicans have dubbed it "Trumpapalooza" – amounts to a risky bet that he can mobilize the voters who carried him to the presidency two years ago, despite opinion polls showing his popularity is at an all-time low.
It remains to be seen whether Trump can bring back critical swing voters who have drifted away from Trump's party amid growing dissatisfaction with the cost of living and the war on Iran.
"I'm asking you to pretend that I'm on the ballot," Trump told the convention on Wednesday night, a line that may have pleased Democratic campaign strategists just as much as MAGA voters.
A MARINE, YALE LAW GRAD AND AUTHOR
A Marine veteran and Yale Law School graduate, Vance first gained national prominence through his memoir "Hillbilly Elegy," which recounted his upbringing in a working-class community battered by industrial decline and his family's struggles with poverty and addiction.
He has argued for using tariffs and other government policies to support domestic manufacturing, embraced restrictive immigration policies and opposed a more interventionist U.S. foreign policy, positions that have made him a central figure in debates over the future direction of the Republican Party.
While Republican officials had described the convention as an opportunity to tout Trump's policies, the first day of the convention focused heavily on attacking Democrats as extreme on topics such as transgender women in sports and border security – cultural issues that animate many Trump supporters.
(Reporting by Nathan Layne, Nandita Bose and Steve Holland; Writing by Joseph Ax and Daniel Trotta; Editing by Howard Goller)
