WASHINGTON (Reuters) - Democratic presidential contenders Joe Biden and Bernie Sanders faced off on Sunday in their first one-on-one debate, a key moment before votes in four states on Tuesday that could give Biden an insurmountable lead in the party’s White House race.

Democratic U.S. presidential candidate former Vice President Joe Biden listens as Senator Bernie Sanders speaks during the 11th Democratic candidates debate of the 2020 U.S. presidential campaign, held in CNN's Washington studios without an audience because of the global coronavirus pandemic, in Washington, U.S., March 15, 2020. REUTERS/Kevin Lamarque

The former vice president and the U.S. senator from Vermont initially focused their discussion on the coronavirus pandemic, which has caused them to rethink their campaign tactics and moved the debate to Washington rather than Arizona.

Here are key quotes:

CORONAVIRUS CRISIS

“This is bigger than any one of us, this calls for a national rallying,” Biden said. “First of all, we have to take care of those who are in fact exposed or likely to be exposed to the virus.” He added the country should immediately begin figuring out how to add to hospitals’ capacity to treat patients.

Sanders blasted Republican President Donald Trump’s response to the coronavirus, saying the “first thing we have got to do ... is to shut this president up right now because he’s undermining the doctors and the scientists who are trying to help the American people.”

“It is unacceptable to have him be blabbering with unfactual information which is confusing the general public,” Sanders added.

MEDICARE FOR ALL

Sanders said the outbreak showed the need for a Medicare for All system that would replace private health insurance with a government-run system.

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“Let’s be honest and understand that this coronavirus pandemic exposes the incredible weakness and dysfunctionality of our current healthcare system. ... We are spending so much money and yet we are not even prepared for this pandemic.”

Biden rejected the idea, saying: “What is it we need? Listen to the experts. And with all due respect to Medicare for All, you have a single-payer system in Italy, it doesn’t work there, it has nothing to do with Medicare for All, that would not settle the problem at all.”

Sanders responded that the “bottom line is, we need a simple system which exists in Canada, which exists in countries all over the world, and that is, if you are an American, you get the healthcare you need – end of discussion.”

DISAGREEMENTS OVER ‘DARK MONEY’

Sanders vowed to take on corporate interests including Wall Street and the health insurance and fossil fuels industries.

“You don’t take campaign contributions from them, you take them on and create an economy that works for all,” he said.

Biden said he had proposed federally funded elections 30 years ago and invited Sanders to join him, saying his average campaign contribution was $44.

“Bernie’s implication is somehow I’m being funded by millionaires,” Biden said. “In Super Tuesday and before that, Bernie outspent me 2, 3, 4, 5, 6-to-1. And I still won. I didn’t have any money and I still won!”

‘RESULTS NOT A REVOLUTION’

Biden said the coronavirus would require an immediate response, not the type of systemic overhaul that Sanders has argued for.

“People are looking for results not a revolution ... we can do that by making sure we make everybody whole who has been so badly hurt in terms of they lose a job, in terms of not having the ability to care for their children, in terms of the healthcare costs .. we can make them whole, now, and put in process whereby they are all made whole. That has nothing to do with the legitimate concern about income inequality in America. That’s real. But that does not affect the need for us to act swiftly,” Biden said.