In what was hands-down the most appalling presidential debate in American history, Donald Trump pummeled Joe Biden brutally and relentlessly for over 90 minutes in Cleveland on Tuesday night.

Trump can't have helped his chances for re-election. He came into the debate trailing Biden by 7 points, and the voters who've been fleeing from the president — suburbanites, women, working-class people from the upper Midwest — are unlikely to be wooed back by 90 minutes of the kind of rude, obnoxious bullying and sneering aggression one expects from a heavyweight boxing match or an afternoon listening to Rush Limbaugh. But we shall see.

What can't be denied is that Trump hit Biden over and over again, barraging him with lies, half-truths, blustering exaggerations, and a torrent of insults. "There's nothing smart about you, Joe," the president said in the opening minutes of the debate. "They're going to dominate you, Joe," he added a few minutes later, referring to the radical left, while talking over the former vice president, thereby illustrating Biden being dominated.

It took less than 20 minutes for Biden to lose his cool for the first of many times, exclaiming, "Would you shut up, man," after Trump refused to let his opponent speak without constant interruption. Later he added, "you're the worst president America's ever had," and, in exasperation, "it's hard to get any word in with this clown." I can't have been the only viewer to watch the display with mounting disgust — about Trump, yes, but also about the fact that our democracy has sunk to such depths.

Considering what he was up against, Biden did fine. No one could have come away from Trump's machine-gun barrage of bile anything other than diminished. How can one respond to a man who barks one lie after another while refusing to keep his pestilential maw shut for a mere two minutes so his opponent can speak? Try to respond to one lie and he lets loose another four and drowns you out with them before you're done.

But the Trump campaign came into the debate pushing the line that Biden is a senile old man. He more than demonstrated that isn't true, though much of the time Biden did give off the air of someone understandably overwhelmed by an onslaught of verbal violence. Most of all, Biden came off like an ordinary politician, citing policies and data and hitting the president over his record while occasionally trying to raise his own rhetoric to the lofty heights traditionally favored by men and women in public life, seeking the honor of winning its highest office.

Trump was something else entirely — some kind of post-truth, street-fighting, full-spectrum bulls**t artist. Say anything. Dominate constantly. Display no warmth. No compassion. No empathy. Just fight, fight, fight. Kick everyone's ass, including that of the moderator, Chris Wallace, who repeatedly tried and usually failed to impose order on the chaos.

The Republican voters who flocked to Trump during the 2016 primaries loved this about him. "He fights!" was their mantra. And so he does. But the American electorate isn't the Republican base. Trump has made this error from the beginning, and the fluke of the outcome of his contest against Hillary Clinton four years ago convinced him to repeat it ever since. The result? An approval rating far underwater for the entirety of his presidency and a race for re-election that he is losing handily.

Tuesday night was at once an audacious gamble for Trump and the most obvious play for him — an effort to demonstrate before a skeptical world that he can turn around his floundering campaign and win a shocking upset victory once again by trying the same old trick of treating the country as if it watches Fox News as obsessively and with as much relish as he does. Trump is utterly incapable of running to the center of public opinion, of making an appeal to a broader range of voters. So he just gets louder and meaner with the same old right-wing Republican message, hoping and expecting that a wider swath of the public will submit to the assault.

All who care about the fate of American democracy need to hope that this is a gamble Trump will lose. Down the path Trump has opened up in our politics lies moral darkness and national decline. We will either begin to right ourselves and reverse course five weeks from now by repudiating him and everything he stands for — or the darkness and decline will deepen.

That is the real choice confronting voters on Nov. 3.