Democratic presidential hopeful former vice president Joe Biden (center) arrives on stage with his wife Jill Biden and sister Valerie Biden Owens for a Super Tuesday event in Los Angeles on Tuesday. Photo: AFP

Seeking a decisive win in the Michigan primary, Joe Biden was joined onstage in Detroit on Monday by two former Democratic presidential rivals, Cory Booker and Kamala Harris, in the latest sign that the party establishment is lining up behind him.

Biden, former vice president, squares off against Senator Bernie Sanders on Tuesday in Michigan and five other states in the battle for the Democratic presidential nomination.

A win by Biden in industrial Michigan, which is the biggest prize in Tuesday's voting, could leave Sanders and his campaign reeling.

The highly coveted support from Booker and Harris could give Biden even more currency with African-American voters in Michigan and elsewhere as he seeks his party's nomination to take on Republican President Donald Trump in November.

"There is one man now who is ready to go to the center of the arena, who is our best shot to beat Donald Trump," Booker told the raucous crowd of 2,000 at a Detroit high school.

"I believe in Joe. I believe in Joe," Harris said. "I know Joe. And that's why I'm supporting him."

As a marching band played, Biden stood arm in arm with Harris, Booker and Michigan Governor Gretchen Whitmer in a gesture of growing Democratic unity. "Folks, look, we're going to unite Democrats, Republicans, independents of every stripe. That's what the nation needs. We've got to bring the country together," Biden said.

Over the past nine days, Biden has powered to the lead in the contest for the Democratic nomination. A wave of endorsements by his former rivals has made him the clear standard-bearer for the Democratic Party's moderate wing, while Sanders represents the party's more liberal elements.

The scene in Detroit on Monday night was reminiscent of the day before Super Tuesday, when he was endorsed in rapid-fire fashion by former presidential rivals Pete Buttigieg, Amy Klobuchar and Beto O'Rourke.

Reuters