Biden, Sanders Attack Trump On Virus -- And Spar On Record

White House hopefuls Joe Biden and Bernie Sanders launched a joint attack on Donald Trump's response to the coronavirus pandemic as they faced off in a high-stakes debate Sunday, accusing the president of undermining his own scientists with misinformation.

The two rivals also sparred about their record, taking advantage of the first one-on-one format of the marathon campaign to engage in extended -- though civil -- policy clashes on everything from universal health care and climate change to deportations and foreign policy.

But with Biden appearing to have a good night, riding high as the frontrunner following three weeks of strong performances in multiple primaries, the 77-year-old made a splash by saying he will "commit" to picking a female running mate if he is the Democratic nominee.

Sanders said he would "in all likelihood" do the same, following the most diverse nomination contest in US history that saw no fewer than six women in the running to take on Trump in November.

Going head to head days before four large states hold Democratic primaries, the two main candidates left in the race stood six feet (1.8 meters) apart and elbow bumped one another at the start of a televised debate held with no live audience as a virus precaution.

Sanders, the 78-year-old underdog, took a stinging shot at the president, accusing him of fomenting confusion and eroding public trust in a time of crisis.

"We have to shut this president up right now because he's undermining the doctors and the scientists who are trying to help the American people," Sanders added, referring to multiple Trump statements at odds with expert views.

"It is unacceptable for him to be blabbering unfactual information that is harming the American public."

Biden essentially agreed, saying: "the existential threat to the United States of America is Donald Trump."

With the debate overshadowed by the fast-moving health crisis, Biden and Sanders spent the first half-hour on how to address the pandemic which has already caused almost 70 deaths and more than 3,600 coronavirus cases nationwide.

"We're at war with the virus," said the former vice president.

"I would call out the military. Now," he added, warning that the Pentagon and the Federal Emergency Management Agency must step in immediately to dramatically expand the number of intensive care beds.

"The present system can not handle the surge that is likely to come," he said.

Sanders called for "aggressively" ramping up testing but also for expanding the safety net to make sure Americans are not pushed deeper into economic crisis.

"What happens if I'm sick? It's going to cost thousands of dollars for treatment. Who is going to feed my kids?" Sanders said, putting himself in the shoes of a workingclass parent.

This 11th Democratic debate has placed the most intense spotlight yet on the duel between the former vice president and the leftist US senator from Vermont.

Of the four states voting Tuesday, Florida, Illinois and Ohio have among the largest troves of Democratic delegates at stake.

Both candidates have cancelled planned rallies, and on Sunday they acknowledged shifting from live gatherings to televised or online events -- and that they are each taking precautions like routine hand-washing to avoid getting infected.

Scrapping live events could pose a particular handicap to Sanders, who has consistently mobilized large and enthusiastic crowds.

He may find one advantage. The pandemic "exposes the incredible weakness and dysfunction of our current healthcare system," said Sanders, who advocates a government-run system that expands coverage to all Americans.

Biden, after a near-calamitous start to the primary season, has staged a spectacular comeback.

The states voting Tuesday, which all show Biden with double-digit leads in polling, should help him consolidate his lead, particularly in Florida where he holds a 40-point advantage.

Sanders was the campaign's putative leader just weeks ago, but he is the clear underdog now.

"If I lose this thing, Joe, I will be there for you," Sanders said, in a revealing moment.

But he expressed worry that Biden would not be able to rally young and Latino voters, two crucial constituencies.

"I have my doubts that Biden's campaign can generate that energy and excitement and voter turnout," Sanders said.

For some, Sanders' continued campaign was a way to gain a last bit of leverage before finally dropping out -- to help advance elements of his "political revolution" and bring some of his progressive ideas more firmly into the mainstream.

But as Sanders repeatedly promoted his Medicare for All plan, Biden pushed back saying it was unlikely to pass Congress.

"We have problems we have to solve now," Biden said. "What's the revolution going to do? Disrupt everything in the meantime?"