Two white-haired men in their 70s bumped elbows in greeting, then retreated to lecterns placed at a CDC-approved distance apart in CNN’s Washington studio for a two-candidate Democratic debate amid the coronavirus crisis.

The loss of that simple, civil gesture — the handshake — made clear how strange and unnerving the times have become. The handshake is pro forma. It’s not intimate or even particularly friendly. It’s a formality. The new elbow greeting feels chummier because it’s casual — something young teammates might do in lieu of a high-five because those are off limits now, too. It was odd to see it executed by a couple of suits.

The bump was a performance for the TV audience. Who else could it be for since there was no audience in the room? It was a flourish, something to underscore that these are science-believing candidates, unlike the president they both hope to defeat — the one who was just heartily shaking hands in the Rose Garden.

Former vice president Joe Biden stood with notably erect posture. His red tie was standard issue. His crisp white shirt reflected light onto his face as he periodically looked down to flip the pages of his legal pad. He squinted at the three moderators, clutched a pen in his right hand and seemed to draw focus from the invigorating momentum he now has in the delegate race.

To his left, Sen. Bernie Sanders (I-Vt.) hunched forward in a dark suit that looked a tad too big. He was a study in gray. His suit read as charcoal. His tie was a sober blue-gray. And his shirt continued the drab color story. Sanders was a human storm cloud — all hectoring darkness. A voice of doom.

Sanders talked of “crooks,” “ripping us off.” How come? How come? How come?

Sanders used every hand gesture in his rich repertoire. He pointed and jabbed and stretched his fingers wide and palmed the air. He waved his arms for emphasis and in frustration. He turned his body toward his competitor and went on a tear about Biden’s statements and votes that happened a lifetime ago, long before the novel coronavirus pandemic, the tanking economy, the shuttered everything, the hoarding of toilet paper and the rise of a now-inescapable question: “Will we survive this?”

Sanders’s outrage was aimed at, of all things, getting a more comprehensive explanation of Biden’s historical policy positions on Social Security — positions that in some cases go back to when neither of them was old enough to qualify for it.

“Joe! Joe! Joe!” Sanders demanded answers. Sanders demanded acquiescence. Sanders demanded because that is his operating principle.

The definitive guide to Bernie Sanders’s hand gestures

Without a studio audience to periodically applaud or cheer its approval, to lend its support to his talk of a revolution, Sanders — for the moment — was not the leader of a movement but a solitary man shouting into a microphone.

“People are looking for results, not a revolution,” Biden said, as he launched into a list of what he would do in the short-term to deal with the coronavirus pandemic, while Sanders was speaking of the systemic failures of the health-care system and the need for Medicare-for-all.

The lack of an audience seemed to have a calming effect on Biden. He also seemed to benefit from not having the whipsawing effect that comes from a herd of candidates onstage all jockeying for speaking time. When Biden wasn’t having his say, his hand rested on the sides of the lectern. At first, he addressed his responses to the moderators. Then, when he turned toward Sanders, he did so with a casual mien with one hand resting at his side.

He spoke of his intimate knowledge of the health-care system, not just as a politician but also as a father. He mentioned a friend pantomiming outside of a nursing home because of the heightened risks faced by the elderly during the pandemic.

Sanders was on a full-frontal attack. He spoke of the needs of average American workers — nameless and impersonal — along with the greed of banks and oil companies. Sanders argued ideology; Biden made everything personal.

During one segment of the debate, Sanders repeatedly referred to Ebola instead of the coronavirus before he finally corrected himself after the third misstatement. Did anyone really need that little fillip to our collective horror? The debate moved on to other topics, to immigration and climate change. For a while, it got stuck in the past.

Biden promised to have a woman as a running mate. Sanders said, yeah, in all likelihood he would probably have one too.

Yet, what was most memorable? The candidates talked of hand sanitizer and hand-washing, virtual campaigning and not touching their faces. They both said they are healthy. At one point, Biden coughed. At another, Sanders wiped his nose. That’s what people do. Now, it’s all fuel for angst.

Biden offered near-term guidance. Sanders spoke of far-reaching fixes. Biden focused on surviving the current storm. Sanders thundered on about just how awful the storm was going to be.