It’s also a meaningful pledge, now that a historically diverse primary field — which included a record number of female presidential candidates — has narrowed to two white men in their 70s. Sanders, meanwhile, hedged on whether he would select a woman rather than pledging it outright, losing the chance to join Biden in the headlines as committing to a female VP. That’s a win for Biden.

Otterbein: Both candidates had decent debate performances, but Biden was ultimately the winner of the night because he is the frontrunner and he didn’t fall flat on his face.

Sanders’ strongest moments were when he took Biden to task over his climate change agenda and record of entertaining cuts to Social Security. And they were strong: Biden made misleading remarks about his past comments about Social Security, and Sanders at one point seemed to force him to acknowledge what he’d actually said. It’s the sort of exchange that could have made a big difference for Sanders, say, before South Carolina voted. But Sanders didn’t have a knockout moment — and at this late stage in the race, that’s likely what he needed.

Siders: Biden only had to keep it respectable to win this debate, with an imperative simply to avoid any lapse that might make his supporters in upcoming states think twice. That was a low bar to begin with, and Biden cleared it and then some.

He made news by pledging to pick a woman for vice president. He sidestepped Sanders’ most stinging critiques from a position of strength, inviting Sanders, for example, to “join me” in reforming campaign finance laws. And he cast himself as above the political fray — in an election he called “bigger than either of us.”

How did the coronavirus pandemic change the debate and the exchange between these two candidates?

Siders: It changed everything — but still, less than I’d expected. First, the changes: That elbow bump at the opening was not just cause for a chuckle, but a visceral reminder that these two candidates — and everyone else — are facing a common challenge together. Coronavirus shaped a more substantive health care debate than candidates have had in any of their previous meetings, and it exposed the differences between Biden’s emphasis on leadership in the moment versus Sanders’ emphasis on systemic change.

But given the gravity of the moment, I had not expected that the candidates could talk at length about any subject beyond the context of coronavirus, and that was wrong. This was also a substantive debate on issues ranging from Social Security to climate change and foreign policy. For whole stretches, a viewer could almost forget the pandemic shutting all of us inside.

Otterbein: There was no audience, and it was amazing. The networks should consider scrapping debate audiences forever.

Unfortunately — and even though the candidates started and ended the debate on the subject — coronavirus did not take up as much time as it could and should have, given how much it looks like it will upend our lives, economy and health care system.