Detroit (CNN) Former Vice President Joe Biden called himself a "bridge" to future Democratic leaders Monday night as he campaigned with Sen. Kamala Harris of California, Sen. Cory Booker of New Jersey and Michigan Gov. Gretchen Whitmer.
"Look, I view myself as a bridge, not as anything else," Biden said. "There's an entire generation of leaders you saw stand behind me. They are the future of this country."
The nod to three people expected to be considered for the vice presidential nomination was the most direct the 77-year-old former vice president has been about how he views his role within the party.
He has long pledged to return the nation to pre-President Donald Trump normalcy. But he and his aides have declined to address whether, if elected, he would run for a second term in 2024. He has said only that he would not run again if he were in poor health.
In town halls and other events, Biden has repeatedly been asked by voters who he would choose as his running mate. He's often said he would seek someone who is "simpatico" on policy issues.
His comment comes as the generation of Democrats he outlasted in the party's presidential primary broadly endorse him against Sen. Bernie Sanders of Vermont.
A week ago in Texas, Biden said that another ex-rival, 38-year-old former South Bend, Indiana, Mayor Pete Buttigieg, reminded him of his deceased son, Beau Biden, and that if the race had occurred six years later, Biden would have been the one endorsing Buttigieg.
On Monday night, Biden singled out Whitmer, saying that her agreeing to become his national campaign co-chair would "send a powerful message all over Michigan and beyond Michigan."
He praised the slogan she had plastered across her campaign bus during the 2018 governor's race.
"Governor, when I hear that great line you say -- just 'fix the damn roads' -- let's just fix the country," Biden said.
Harris and Booker were the latest in a round of former Democratic primary rivals to endorse Biden after his February 29 blowout victory in the South Carolina primary.
Minnesota's Sen. Amy Klobuchar and Buttigieg campaigned with him in Dallas before last week's primaries. Former Rep. Beto O'Rourke of Texas was his closer at an electric rally there.
Harris and Booker joined Biden on Monday in Michigan, with Booker appearing first with Biden in Flint and Harris joining the two and Whitmer onstage in a Detroit high school gymnasium.
Harris and Booker had campaigned aggressively against Biden as his rivals for the Democratic nomination. Harris saw a brief surge in Democratic primary polls after she attacked Biden's past opposition to federally mandated school busing in a July debate. Booker, on CNN after a September debate, said there were "a lot of people concerned about Joe Biden's ability to carry the ball all the way across the end line without fumbling."
On Monday night in Detroit, though, those fights were forgotten.
Harris, in particular, struck an emotional chord, detailing her relationship with Beau Biden when she was California attorney general and he was Delaware attorney general.
"I got to know Joe through Beau," she said, as the gymnasium full of people fell silent. "It's a rare thing to see such a special relationship a between a father and his son. It was an extraordinary relationship that they had."