Democratic comeback candidate Joe Biden boasted on the eve of the crucial “mini Super Tuesday” primaries in Michigan and elsewhere of how he will vanquish his leftwing rival Bernie Sanders – but also appeared to acknowledge his place as an ageing party grandee by calling himself “a bridge” to a future generation of leaders.

Turning to his newest high-profile endorsers at a raucous rally in Detroit on Monday night, Biden indicated the younger African American senators Kamala Harris of California and Cory Booker of New Jersey onstage with him, who both recently saw their hopes of becoming the 2020 nominee dashed.

“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.”

Biden, newly confident since an unexpected landslide in the South Carolina primary and a convincing sweep of almost all the states from Virginia to Texas that voted on Super Tuesday – with Sanders picking up Colorado, Utah and California – appeared buoyed.



“Senator Sanders likes to say: ‘We’re only going to beat Donald Trump by generating excitement and turning out more voters.’ Well guess what? On Super Tuesday we turned out 70% more voters … and in South Carolina we turned out 22% more voters,” Biden said, eliciting chants from the elated crowd of “Let’s go Joe!”

“He’s right,” the moderate Biden added, but indicated those present. “We are going to turn out the Democratic party.”

Joe Biden speaks during a campaign rally in Detroit, Michigan, on 9 March. Photograph: Mandel Ngan/AFP via Getty Images

Michigan is the big prize on Tuesday, a vital swing state with the support of 125 pledged delegates up for grabs, the party figures who ultimately anoint the party nominee.

The rally came as evidence mounted that the party is coalescing behind him and Sanders’ path to the nomination as a democratic socialist is petering out.

Michigan’s primary is closely watched because it is viewed as Sanders’ best shot to turn around his struggling campaign, and his 2016 surprise upset of Hillary Clinton in the state dramatically shifted that race’s momentum.

The Vermont senator has thrown heavy resources into repeating that success.

In the days leading up to the election, Sanders crisscrossed the state, making three times as many Michigan stops as Biden.

The campaign rolled out key endorsements from supporters including Jesse Jackson and progressive Michigan leaders, while surrogates such as the effervescent freshman congresswomen Rashida Tlaib and Alexandria Ocasio-Cortez, together with the popular Ivy League public philosopher Cornel West, joined Sanders on stage.

Despite the effort, five Michigan polls released on Monday showed Biden with commanding leads of between 12 and 41 points over Sanders.

Biden’s polling numbers are similarly strong in several other states holding Tuesday primaries. He’s expected to win by a landslide in Mississippi, while the latest Missouri poll put the former vice-president up 30 points.

Washington state polling shows a tight race, an important one for Sanders to win, but even a narrow Biden loss there would do little to trip him up.

Biden already leads Sanders by about 90 delegates and he would tally an all but insurmountable lead with five or six strong wins.

The Michigan primary is “the start of the end of Trump”, said Detroit resident Tia Simmonds, among the exuberant crowd.

“The wind is at his back, baby. The wind is at his back,” she said. “He understands Detroit. He understands America, all of us, and no – there’s no going back. He’s gonna win it.”

The crowd loved Harris and Booker joining Biden onstage. Both have been floated as potential running mates.

Some Democrats are especially enthusiastic about the possibility of Harris joining the ticket. Biden has said he will probably choose a woman, and Harris, who ended her presidential bid in December, could help turn out black voters.

Kamala Harris and Cory Booker during a rally for Joe Biden in Detroit, Michigan, on 9 March. Photograph: Jeff Kowalsky/AFP via Getty Images

In her brief speech, Harris told the audience that “we’re celebrating” and focused on Trump and Biden’s electability.

“There’s one man who is ready to go to the center of the arena, and our best shot to beat Trump, to heal the soul of America, to bring dignity back to that office, the best one to stand up for all in America – his name is Joe Biden,” she said.

Booker also focused on Trump, who he accused of trying to “tear America apart”.

“It seems like the president takes great pleasure in pitting Americans against Americans,” Booker said.

Biden’s confidence in his position also showed in his speech to the roughly 1,000 supporters. He touted the Obama administration’s contributions to Michigan, then pivoted to Trump.

He spoke for about 20 minutes – longer than the approximately seven minutes he clocked at some recent stops. Critics have said the Biden campaign is limiting his speaking time to avoid gaffes. In recent weeks, Trump and Republicans have increasingly claimed that Biden is suffering from mental decline, foreshadowing their strategy should Biden secure the nomination.

The former vice-president’s decision to hold the primary eve rally in a city that’s 80% black probably stems from Clinton’s failures here in the state. Sanders in 2016 won a larger share of the black vote than expected, while Clinton did not campaign in Detroit ahead of the general election. The significant drop in black voters in Michigan between 2012 and 2016 partly contributed to her stunning loss to Trump.