NEW YORK    -    Formally launching his third presidential campaign, Joe Biden appealed for party and national unity while accusing Donald Trump of leading America with “a clenched fist, a closed hand and a hard heart”.

Biden appeared at Eakins Oval in Philadelphia on Saturday afternoon, two days ahead of a Trump rally elsewhere in Pennsylvania, one of the states in which blue-collar swing voters delivered the White House to the Republican in 2016.

Introduced by his wife, Jill Biden, the former vice-president called on Democrats to eschew the politics of division and to “fight for, defend and earn democracy”.

“I know there are times when only a bare-knuckle fight will do,” he said. “I know we have to take on Republicans to do what’s right without any help from them.” But, he said, “we are the United States of America and there is not a single thing we cannot do if we are together.”

“If the American people want a president to add to our division,” he said, “to lead with a clenched fist, closed hand and a hard heart, to demonise opponents and spew hatred – they don’t need me. They already have a president who does just that. I am running to offer our country – Democrats, Republicans and independents – a different path.”

Biden was a senator from Delaware for 36 years and vice-president to Barack Obama from 2009 to 2017. He was a relatively late entrant to the sprawling field seeking the Democratic nomination in 2020, which has now reached 23 candidates.

Biden has been criticised for his behaviour towards women, including his role in hearings into allegations of sexual harassment against the supreme court justice Clarence Thomas; for his congressional record on racial issues; and for a perceived lack of progressive policies and appeal.

The 76-year-old nonetheless has a handy lead in most primary polls, clear of prominent opponents including Bernie Sanders, Elizabeth Warren and Pete Buttigieg. In Philadelphia, Biden repeatedly appealed for party unity. It would, he said, stand counter to the divisive rhetoric of the Trump presidency.

“Some say Democrats don’t want to hear about unity,” Biden said. “That they are angry – and the angrier you are, the better. That’s what they are saying you have to do to win the Democratic nomination. “Well, I don’t believe it. I believe Democrats want to unify this nation. That’s what we’ve always been about. Unity.” He said he would not speak ill of any other Democratic candidate, although when a repetitive whistling sounded in the background to the rally, Biden joked: “That must be Bernie.” Biden leads Trump in general election match-ups, among them a headline-grabbing 11-point lead in Pennsylvania in a Quinnipiac poll released this week.

In return, Trump has begun to attack Biden regularly, coining the nickname “SleepyCreepy Joe”. Four years younger than the former VP, at 72, the president has denied multiple allegations of sexual misconduct and assault.

Campaign volunteers seek shade before the kickoff rally for Joe Biden in Philadelphia. Biden’s conciliatory tone and manner may work as a powerful antidote to Trump’s relentlessly caustic rhetoric.

 “He counters Trump by not being angry or dismissive,” Carl Tobias, a law professor at the University of Richmond in Virginia, told the Guardian on Saturday, also noting Biden’s appeal to “blue collar voters, especially in Pennsylvania, Michigan and Ohio, promising to unite rather than divide Americans, to work with US allies, to honor the rule of law and to behave like a normal president.” About 2,000 people were expected to attend Biden’s Philadelphia speech, campaign sources told media. Other candidates have claimed bigger crowds for their kick-off rallies, among them the California senator Kamala Harris. About 20,000 attended her speech in Oakland in late January. Like other candidates, however, Harris does not have the kind of national name recognition enjoyed by Biden. In a long political career, Biden has mounted two runs for the Democratic presidential nomination.

In 1987 he dropped out of the primary race amid controversy over alleged plagiarism from sources including speeches by the British Labour leader Neil Kinnock. In 2007, he failed to attract support in a race dominated by Obama and Hillary Clinton.