The debate, which was originally scheduled to take place in Phoenix but moved last week to Washington, D.C., due to the coronavirus outbreak, began with the two candidates substituting the normal shaking of hands with the bumping of elbows, as recommended by health officials.
No live audience was present for the event, as a precaution to mitigate the spread of the virus. Univision moderator Ilia Calderon filled in for Jorge Ramos after he came into contact with someone who was exposed to the virus.
The first question of the debate centered on COVID-19, the disease that's sickened more than 167,000 people and killed 6,400 worldwide as of Sunday. In the United States, the number of cases is at more than 1,600 and 41 deaths, according to the Centers for Disease Control and Prevention.
Biden said this epidemic is "bigger than any one of us" and called for a "national rallying" of Americans to come together.
He said if he were president, he'd increase testing, ensure every state had at least 10 drive-through testing locations and plan for additional hospital beds, as well as deal with the economic fallout, including ensuring those who can't get paid due to the virus' effects can still pay their rent and small businesses can receive interest-free loans.
Sanders said the first thing the United States must do, whether or not he is president, is "shut this president up right now."
He said President Donald Trump should be muzzled as he is "undermining" the doctors and scientists who are attempting to mitigate the coronavirus crisis.
"It is unacceptable for him to be blabbering with un-factual information, which is confusing the general public," he said.
Sanders said the United States must next "move aggressively" to ensure every American knows that when they get sick with the virus all associated medical costs will be covered.
"This is an unprecedented moment in American history," he said. "Now, I obviously believe in Medicare for All -- I will fight for that as president -- but right now in this emergency, I want every person in this country to understand that when you get sick, you go to the doctor. When you get sick, if you have the virus, that will be paid for. Do not worry about the cost right now because we're in the middle of a national emergency."
Sanders said the capacity of hospitals must be increased so they can deal with a virus peak of hundreds of thousands of people, a measure Biden agreed with.
Biden added the crisis is akin to being attacked by a foreign enemy, and America must do all it can to defeat it.
"This is like a war, and in a war, you do whatever is needed to be done to take care of your people," he said. "Everything that you need in terms of dealing with this crisis would be free."
Medicare for All
The debate over a COVID-19 response veered in and out of talk of healthcare, specifically Sanders' call to reform Medicare to be a single-payer system that covers every citizen.
Biden attacked the idea, stating Italy, which has the second-highest number of COVID-19 infections with nearly 25,000, is proof a single-payer system doesn't work.
"It doesn't work there," he said. "It has nothing to do with Medicare for All. That would not solve the problem at all."
He said by treating the crisis as a national emergency, meaning associated medical costs would be covered by taxes, is how it should be handled.
Sanders rebutted that the crisis has made apparent "the dysfunctionality of the current healthcare system," which he argued isn't a system but a network of private insurers.
"We don't have a system," he said. "We got thousands of private insurance plans -- that is not a system that is prepared to provide healthcare to all people. In a good year, without the epidemic, we're losing up to 60,000 people who die every year because they don't get to a doctor on time."
Biden disregarded the idea of a political revolution, of which Medicare of All is a part, saying there are problems that need to be solved now.
He said Sanders' plan, if it could be passed, wouldn't be in effect for at least four years, while his plan would restore cuts made to Obamacare, lower prescription costs and ax hidden bills while ensuring a public option.
"I can get that done if I'm president of the United States of America," Biden said. "What people want is hope and they need it now, not four years from now."
Sanders said the United States' inability to offer its citizens healthcare similar to the single-payer option most wealthy nations have is the result of the imbalance in the country's power structure that is controlled by the billionaires and companies.
"If you want to make real changes in this country, if you want to make an economy that works for all and not just a few, if you want to guarantee healthcare to all not make a hundred billion in profit for the healthcare industry, you know what you need? You need to take on Wall Street," he said. "You need to take on the drug companies and the insurance companies and the fossil fuel industry."
Foreign policy, authoritarianism
Concerning authoritarian leaders, Sanders said they should be condemned.
"As president of the United States, unlike Donald Trump, I will put the flag down and say that in this country and in this world we've got to move toward democracy and human rights," he said.
When asked if authoritarian leaders should be judged by their human rights violations and not their achievements, Sanders said China is an authoritarian society but one cannot deny that extreme poverty in the country has receded compared to decades ago.
"That's a fact," he said. "So, I think we condemn authoritarianism whether it's in China, Russia, Cuba, anyplace else, but to simply say that nothing ever done by any of those administrations had a positive impact on their people would, I think, be incorrect."
Biden then defended former President Barack Obama praising the Fidel Castro regime in Cuba as part of efforts to change the island nation's policy so the United States could help to open it up.
He then reacted to Sanders' comment on China lifting citizens from extreme poverty, stating the Asian nation is an authoritarian dictatorship and the increase of wealth it has brought to its people has been "marginal" compared to its human rights transgressions.
Sanders rebutted, stating he did call China a dictatorship and an authoritarian country but "it's a little bit absurd if we're going to look at the world the way it is" to disregard the accomplishments of those nations.
Earlier in the debate, Sanders condemned China, where the coronavirus outbreak began in December, for attempting to initially downplay the severity of its epidemic by censoring those who attempted to inform others about the crisis. But he also said now is not the time to punish the Asian nation but to work with it on ending the pandemic.
"If there was ever a moment when the entire world is in this together, got to support each other, this is that moment," he said.
Biden also said the United States should work with China. He said he insisted U.S. experts be sent to the Asian nation and that there should be consequences if they were denied entry.
The debate followed strong showings by Biden on Super Tuesday and last week's primaries, and ahead of contests scheduled for Tuesday in Arizona, Florida, Illinois and Ohio.
Election officials in Georgia on Saturday delayed the state's March 24 primary to May 19 and Louisiana moved its April 4 primary to June 20 in response to the coronavirus.
Biden's campaign on Sunday encouraged asymptomatic voters and those not at risk of exposure to vote on Tuesday and for those at risk to take advantage of absentee or vote-by-mail options.
"The right to vote is the most sacred American right there is," he wrote. "State election officials are working closely with public health officials to hold safe elections. If you are feeling healthy, not showing symptoms and not at risk of being exposed to COVID-19: please vote on Tuesday."
Biden pledged during the debate to choose a woman as a running mate.
The race for the Democratic nomination to challenge Trump in November began with several accomplished women vying to become the first female president, including Massachusetts Sen. Elizabeth Warren, Minnesota Sen. Amy Klobuchar, California Sen. Kamala Harris and New York Sen. Kirsten Gillibrand. Rep. Tulsi Gabbard of Hawaii remains in the race.
"There are a number of women who are qualified to be president tomorrow. I would pick a woman to be my vice president," he said.
When pressed by moderator Dana Bash, Sanders said he would also pick a woman as a running mate, "in all likelihood."