Democrats have formally nominated Joe Biden for president, vowing his election would repair a pandemic-battered America and put an end to the chaos that has defined Republican President Donald Trump’s administration.

The second night of the party’s four-night national convention featured elder statesmen such as former presidents Bill Clinton and Jimmy Carter, rising stars of the Democratic Party as well as prominent Republicans, who made the case that Biden would return integrity to the White House and normality to American lives.

Mr Biden’s wife, Jill, an educator, delivered the headline speech from a Delaware high school where she once taught, offering a deeply personal account of how their love helped him heal after his first wife and infant daughter were killed in a car accident.

“I never imagined at the age of 26 I would be asking myself, ‘How do you make a broken family whole?'” she said. The answer, she said, is the same for a broken nation: “With love and understanding.

“If we entrust this nation to Joe, he will do for your family what he did for ours: bring us together and make us whole.”

Throughout the evening, Democratic leaders contrasted Mr Biden’s long experience with what they described as Mr Trump’s deadly mishandling of the coronavirus outbreak and his willingness to corrupt democratic institutions.

“At a time like this, the Oval Office should be a command centre,” Mr Clinton said in a prerecorded video. “Instead, it’s a storm centre. There’s only chaos. Just one thing never changes – his determination to deny responsibility and shift the blame.”

With the four-day convention largely virtual due to the coronavirus, delegates from around the country cast votes remotely to confirm Mr Biden as the nominee in a coast-to-coast roll call that drew instant raves on social media.

After hearing from his home state of Delaware, which went last, Biden appeared live alongside Jill Biden to thank the party for nominating him, more than three decades after his first unsuccessful run for the White House.

“Thank you very, very much from the bottom of my heart,” said Biden, who will deliver his acceptance speech on Thursday. “It means the world to me and my family.”

The program started by showcasing some of the party’s rising politicians, featuring 17 Democrats in a video address, including Stacey Abrams, the one-time Georgia gubernatorial nominee whom Mr Biden considered for a running mate.

Joe Biden has a conference call during the virtual convention.

Democrats again featured a handful of Republicans who have crossed party lines to praise Mr Biden, 77, over Mr Trump, 74, before the November 3 election.

Cindy McCain, widow of Republican senator John McCain, spoke in a video about her husband’s long friendship with Mr Biden. Mr Trump clashed with Mr McCain, who was the Republican nominee for president in 2008, and the president criticised Mr McCain even after his 2018 death.

Republican former secretary of state Colin Powell, a retired four-star general who endorsed Mr Biden in June, was one of several national security officials who spoke on the Democrat’s behalf.

“He will trust our diplomats and our intelligence community, not the flattery of dictators and despots,” Mr Powell said.

“He will stand up to our adversaries with strength and experience.”

Without the cheering crowds at the in-person gathering originally planned for Milwaukee, Wisconsin, TV viewership on Monday was down from 2016. But an additional 10.2 million people watched on digital platforms, the Biden campaign said, for a total audience of nearly 30 million.

Aiming to draw attention away from Mr Biden, Mr Trump, trailing in opinion polls, held a campaign rally in battleground state Arizona.

He called Mr Biden’s immigration plan “radical” and “extreme”, continuing his effort to portray Mr Biden as a puppet of left-wing agitators.

Mr Biden’s vice-presidential pick, Senator Kamala Harris, will headline Wednesday night’s program along with Obama.

The Republican National Convention, also largely virtual, takes place next week.

-AAP