Since modern presidential debates began in 1960 and picked back up again in 1976, winners and losers have been chosen on anything but command of the facts.
Radio listeners thought Nixon had won, he so rhetorically abused John Kennedy in 1960. But Kennedy looked better on camera, because his campaign bribed studio techs to make Nixon look bad through bad lighting and strange camera angles, and the press gave it to Kennedy. In 1980 Carter said he would ask his very young daughter Amy for advice on nuclear strategy. He was then properly pegged an idiot and Reagan won. Reagan hit Mondale in ’84 with a turnaround on the age question, it even got a laugh from Mondale, and Dukakis said in ’88 that if a man raped and killed his wife he did not deserve the death penalty. As such, Reagan in ’84 and Bush in ’88 cleaned up. And we all remember the rush we felt at the “because you’ll be in jail” line in 2016.
Thus, no great oratory, no impressive command of facts or logic, no cut and thrust of debate has ever won an American presidential candidate a debate. It’s how you look, your tone, a clever line, or an opponent’s mistake that wins debates in this country. So it will be with Trump and Biden.
But both campaigns have to manage expectations to get the big win in perceptions, which will translate into a poll bump. Trump needs to raise the bar on Biden, as it’s no great victory beating up on a confused guy. Biden has to lower expectations of himself, given he is likely to get clobbered by Trump. At least that way, by playing off the loss as almost expected and then quickly moving on, Biden can take some of the sting out of his hammering.
The president will be playing to the crowds and the audience, he always does. He will pick a fight with the moderator, his base will love that. Given the moderator of the first debate is Chris Wallace, no Trump fan at all but rather a hereditary creature of the DC press establishment, Trump supporters will watch with glee if the president slams him to the mat once or twice.
Biden will have to keep his mental composure and stay on point. All justifiable jokes aside, Biden has a serious communication problem. He is tangential, uses anachronistic phraseology, and lashes out when challenged. If Trump can bait him into those actions Biden will lose hands down. But if Biden can somehow control and discipline his pitch, maybe, just maybe, he survives only slightly bruised.
This must all be seen in the context of the media environment. No matter who wins the majority of the media, even if Biden completely goes stark raving mad and starts gnawing on the podium while shrieking “mommy!”, will call Biden the winner. If Trump so clearly wins they can’t do that, they will say Trump was a bully and a liar. Expect Trump to win and that to happen.