After a stunning series of wins, Joe Biden has seized the mantle of frontrunner in the 2020 Democratic presidential primary race. Though Bernie Sanders' path to the nomination has narrowed, he persists on his campaign to upset the status quo.

As the coronavirus pandemic grips the US, the candidates met n their first one-on-one Democratic debate of this election cycle.

Without an audience, the former vice-president faced off against the Vermont senator after Elizabeth Warren, Pete Buttigieg and Amy Klobuchar all dropped out following Super Tuesday.

Hawaii congresswoman Tulsi Gabbard remains in the race but did not qualify for the latest debate.

The debate gave the senator his biggest and best chance yet to frame his signature progressive policies to a national audience against the backdrop of the coronavirus crisis and its revelation of the kinds of national failures that his platform aims to address on a systemic and fundamental level.

Mr Biden, on the other hand, used the moment to highlight his front-runner status. As the clear delegate leader in the field, and without a stage of contenders competing for the spotlight, the former vice president was more focused and in-control than in previous debates.

"This is bigger than any one of us", he said.

He underlined their ideological differences, saying voters are "looking for results" and "not a revolution" — what would be a drawn-out political fight — while Mr Sanders stressed the "dysfunction" in government that has led to the inequities Americans are faced with in the midst of the crisis.

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Both men supported picking a woman vice president, and both men rallied around defeating the incumbent in November by committing to campaign for the nominee.

Though Mr Biden's past — potential cuts to Social Security, wavering on abortion rights, supporting the Wall Street bailout, super PAC support — came back to haunt him, the debate fell away from substantive policy decisions and came back to the coronavirus threat, and whether the candidates are prepared to meet it.

The debate was originally scheduled to take place in Phoenix, Arizona but has been moved to Washington DC, days before another round of crucial primaries scheduled for 17 March: Florida (with 219 delegates), Illinois (155), Ohio (136) and Arizona (67).

There is one more Democratic debate in the primary calendar which will take place in April, as long as both Mr Biden and Mr Sanders are still in the race. A date and location for that debate have not yet been finalised.

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