It's been 20 years since I voted for a Republican, and that certainly won't be changing now, with the party's nominee a know-nothing conman who spends his days shredding the civic fabric of the nation for the sake of advancing his personal lust for power, wealth, and attention.

But that doesn't mean that as a centrist I don't struggle to keep my bearings in the storm that is American politics in 2020. The center is always somewhat hard to hold, but it's especially challenging today, with full-force partisan gales blowing from both directions. Nothing would be easier, it sometimes seems, than to give in to the gusts and allow myself to be shoved toward one or the other extreme.

It's not just that the center of gravity in each of the parties is giving way to the powerful centrifugal forces at work in our politics and culture. As I'll explain in a moment, that process is unfolding differently in the two parties, which is one reason I favor the Democrats and consider the Republicans an unacceptable option. But politics is now less about what the two parties actually stand for than about what each party can convincingly claim the other stands for, using the most unhinged, radical statement of anyone within the other party's electoral coalition as evidence that supposedly reveals its hidden essence and agenda.

This is more than mere negative partisanship, which has been intensifying rapidly over the past few decades, with Republicans and Democrats both increasingly motivated to cast their votes more against the other party than for their own. What we see now is often an amped-up virtual-reality form of negative partisanship that exploits the human tendency to fall into the fallacy of composition. This is the temptation to treat a part (and often an unrepresentative part) of a larger whole as uniquely revealing of the character of that whole. The right does this all the time in its reporting on colleges — blowing up an ill-informed far-left statement from a random humanities professor and using it as evidence of the uniformly pernicious influence of universities as such.

There was some of this kind of thing at the Democratic National Convention, but the fallacy is less egregious when Democrats do it because the part of the GOP saying and doing the most extreme and outrageous things is often … the head of the party and president of the United States — the part of the party that's supposed to represent the whole. But Trump goes even further, to embrace even the most radical and delusional factions and personalities in the GOP as long as they offer him their support. This renders the fallacy of composition somewhat less fallacious when applied to the Trumpified Republican Party.

The same cannot be said of the reverse. The Republican National Convention was a wall-to-wall orgy of unjustified generalizations. Democratic voters had more than two dozen options before them in the run-up to the primaries this time around, many of them much further left than the last Democrat to win the White House. Yet the voters opted for Joe Biden, a lifelong moderate with a long track record of seeking conciliation across the aisle, a candidate who promised broad continuity with and modest expansion on the work begun by the solidly center-left administration in which he served as vice president.

Instead of taking issue with this Biden and this Democratic Party, the RNC gave viewers a fun-house version of both. The "real" Democrats are those who want to burn down America, who hate the country and its history, who want to transform it into something wholly different and thoroughly ominous — some kind of a socialist-anarchist dystopia in which criminals run rampant, raping, stealing, and murdering with impunity. Biden might not endorse these aims, but he's too old, feeble, and ideologically enervated to stand against it. He's a Trojan Horse who will deliver these throngs of anti-American radicals to power and then stand impotently by while they ruin everything great about the United States.

It's nonsense. But it's potent nonsense, because it serves as a constant reminder of what's worst — both farcical and civically destructive — about the contemporary left. There's an awful lot of examples at the moment. They range from the woke revolution at The New York Times, to the local government of Washington, D.C., proposing to remove or "contextualize" the Washington Monument and Jefferson Memorial, to universities and corporations forcing employees to participate in ritualized and performative self-denunciations of their own racism, to riots and looting destroying communities and people's livelihoods in Portland, Seattle, Chicago, and other cities.

Just last week, in one of the less well-publicized incidents of left-wing "street politics," a parade of self-described "anti-capitalist" protesters in West Philadelphia tore up a neighborhood adjacent to the University of Pennsylvania, where I teach. Businesses had their windows smashed, and buildings were vandalized — including "a PNC bank, a coffee shop, a pizza parlor, a bar, [and] the Free Library branch at 40th and Walnut Streets."

And for what? No doubt the 60-odd people behind the mayhem rationalized their tantrum-throwing as some noble act of resistance against structural injustice. In reality their actions accomplished nothing positive at all. No effort at police reform will be advanced, no Black lives will be saved, because a library was sacked, some small-business owners took a hit, and a community lost some of its lifeblood. Those who inflicted the damage were just a mob out to break things for the demonic joy of it.

Trump and his Republican parrots are wrong to treat roving bands of self-righteous criminals as uniquely revealing of the true soul of the Democratic Party. They aren't. But in a country with just one major left-of-center party, they are a (small) part of its electoral coalition, just as a less volatile but somewhat larger segment of the party is hesitant to call out such acts — both because they feel the troublemakers' hearts are in the right place even if their tactics are a little too extreme, and because they fear empowering the right with any sign of dissension within the ranks of the left.

Joe Biden and Kamala Harris are not in either camp — and they need to reinforce that fact as often and as forthrightly as they can. They need to do this not just because the Trump campaign has shown that it will be hitting the Biden ticket on the issue every day from now until Nov. 3, and that over time the strategy could prove to be politically potent in the battleground states that the Democrats desperately have to win. They also need to do it because riots and looting and setting fire to the high-rise apartment building that the mayor of a major American city and hundreds of others call their home is wrong and should have no place whatsoever in the politics of a civilized society.

Regardless of what happens over the next 60 days, Donald Trump will deserve to lose the upcoming election. In taking a consistent, unapologetic stand against those on his own side who merit their place on the outer margins of our politics, Biden can demonstrate decisively that he speaks for the center of the country — and that he actually deserves to win.