Biden Sweeps Three States and Takes Commanding Lead, as Virus Reshapes American Politics

“We’ll get through this together,” said Mr. Biden, trying to project a presidential bearing to a rattled nation. He only fleetingly mentioned Tuesday’s results, noting he had “a very good night,” before directly speaking to Mr. Sanders’s youthful supporters, a voting group he is trying to court.

“I hear you, I know what’s at stake, I know what we have to do,” Mr. Biden said. “Our goal as a campaign, and my goal as a candidate, is to unify this party and unify this nation.”

Praising the “remarkable passion and tenacity” of Mr. Sanders and his supporters, the former vice president said he and the senator disagree on tactics but “share a common vision.”

Mr. Sanders did not deliver a speech about the primary results, but earlier in the evening he broadcast his own online address calling for sweeping government action to remedy the economic damage of the crippling virus, including an initiative to give people $2,000 monthly payments for the duration of the crisis.

“We must make certain that this health and economic crisis is not another moneymaking opportunity for corporate America and for Wall Street,” Mr. Sanders said, eschewing any mention of the primaries.

Mr. Biden’s victory in Florida relied in part on a familiar coalition of voters who have supported him in other states, including African-Americans, political moderates and voters over 50, according to a pre-election poll there. But polls suggested that Mr. Biden would also finish narrowly ahead of Mr. Sanders with people who described themselves as very liberal, and that the former vice president would beat him by double digits among voters who said the economic system needed a complete overhaul.

The virus drove down turnout in some Florida localities, but even with the pandemic turnout was still higher than in 2016 in a handful of suburban and affluent communities, such as Naples and suburban Jacksonville. Mr. Biden won both jurisdictions handily, as he has in other upscale precincts since Super Tuesday, a sign of his strength with the sort of voters who could swing the general election.