Former Vice President Joe Biden and Senator Bernie Sanders used Sunday’s Democratic debate to cast themselves as best-positioned person to lead the United States through a global pandemic.

In the latest debate in the race to decide the Democrats’ nominee to run for president, the pair were united in their criticism of President Donald Trump’s response to the coronavirus but diverged on how they would confront the spiralling public health and economic crisis.

Mr Biden pledged to deploy the US military to help with recovery efforts and warned a federal financial bail-out may be necessary to stabilise the economy.

Election 2020 Debate
The two candidates greeted each other with a coronavirus-era elbow bump (Pablo Martinez Monsivais/AP)

Mr Sanders leaned into the same domestic policy proposals that have dominated his campaign, arguing the government-run health insurance system he has long championed would allow the US to respond faster to a health crisis.

The coronavirus outbreak has rapidly reshaped nearly all aspects of American life, shutting schools across the country and significantly curtailing travel.

Virus fears have also halted campaign rallies and prompted some states to delay forthcoming primaries because of warnings from public health officials against large gatherings.

“This is bigger than any one of us — this calls for a national rallying for one another,” Mr Biden said.

Indeed, the stakes in the race for the Democratic presidential nomination have shifted dramatically since Mr Biden and Mr Sanders last debated less than three weeks ago — as have the contours of the contest.

After a sluggish start to the primary season, Mr Biden has surged to the front of the field, drawing overwhelming support from black voters and consolidating the backing of several more moderate rivals who have dropped out of the race.

He is also actively courting the endorsement of Elizabeth Warren, a liberal ally of Mr Sanders who dropped out without throwing her support behind him.

The former vice president appeared determined throughout Sunday’s contest to keep his focus on the general election.

He made direct overtures to Mr Sanders’ loyal supporters and committed for the first time to select a woman as his running mate if he became the Democratic nominee.

After that announcement, Mr Sanders said he would “in all likelihood” do the same.

For Mr Sanders, the reality is that his path to the nomination is rapidly shrinking, and he faces the prospect of more stinging defeats in the four states that vote on Tuesday.

Still, he appeared determined to draw sharp contrasts with Mr Biden throughout the debate, challenging him aggressively on the Iraq War and free trade deals.

He argued that “I have taken on every special interest that’s out there,” adding, “That’s a very different record than Joe’s”.

Mr Biden and Mr Sanders’ prescriptions for addressing the coronavirus outbreak highlighted the contrasting approaches they are pledging to bring to the White House.

Mr Biden, a centrist who backed the 2008 bailout of the financial industry during the recession, warned that another government-backed rescue plan may be needed in the coming months to shore up the economy.

Mr Sanders, a fierce liberal critic of Wall Street, opposed the earlier bailout and said it would be a mistake to take a similar approach now. Instead, he suggested a tax on the wealthiest Americans.

The Vermont senator also repeatedly pushed questions regarding the coronavirus toward a now-familiar debate with Mr Biden over health care.

Mr Sanders argued the troublesome shortages in coronavirus tests and anxiety over the preparedness of the nation’s health care system highlighted why the US should move to the government-run, “Medicare For All” system he has long championed.

“One of the reasons that we are unprepared, and have been unprepared, is we don’t have a system. We’ve got thousands of private insurance plans,” Mr Sanders said.

“That is not a system that is prepared to provide health care to all people in a good year, without the epidemic.”

Mr Biden, who supports adding a public insurance option to the current system, argued a pandemic was not a moment to attempt to push through an overhaul of the American health insurance system, a politically arduous endeavour.

“This is a crisis,” Mr Biden said. “We’re at war with a virus.”

As the debate opened, Mr Biden and Mr Sanders skipped a handshake, greeting each other instead with an elbow bump.

They took their positions at podiums spaced six feet apart in keeping with guidance from the Centres for Disease Control and Prevention for limiting the spread of the coronavirus.

They addressed the nation, and each other, from a television studio in Washington without an in-person audience.