Democracy is in a worldwide slump. So is peace — both the international and the domestic sort. There are lots of reasons. What’s the biggest?

Many pundits blame various kinds of polarization: Left against right, elitist versus populist, blue against red, educated or rich against uneducated or poor, nativist versus cosmopolitan, Sino-Russian autocratic against "Western” democratic and so forth.

I’ll argue that the dichotomy that matters more than any of these is civil versus thuggish. And our problem — in the U.S., Europe, Russia, Brazil, China, the United Nations — is that, lately, the thugs have been winning almost everywhere.

"Thug” comes from Hindi and originally referred to violent gangs of robbers. Nowadays we use the word for hooligans, bullies or other brutes. Among rappers, the term has taken on an ironic twist, but we’ll leave that usage to them.

In essence, thuggishness is intimidation with the threat of violence. It spreads wherever civility breaks down. In places like Germany or Italy after World War I, thugs took to the streets, beating up or shouting down anybody they didn’t like. They called themselves Blackshirts, Brownshirts, Free Corps, Red Fronts and what have you. Contemporary analogs include Oath Keepers, Proud Boys, Night Wolves (a Russian motorcycle club) and other packs. But whether they adulate Mussolini, Lenin, Trump, Putin or any other leader, politics is arguably only a veneer. The underlying phenomenon is thuggishness.

Thugs don’t have to be physically pugnacious to vandalize the public square. It suffices for the violence to be implied, verbal or even subliminal. That’s because aggression in any form ruins the things that make civilized society possible: civics and conversation.

The words "civil” and "polite” both come from Latin and Greek roots that also gave us such words as "city” and "politics.” To "converse” originally meant "to turn toward” one another, with the motivation to connect — and ideally to inch closer to the truth of something, perhaps even to find solutions to common problems. Nuance, contradiction, subtlety, ambivalence and humor are features of such congregating, not bugs.

But when thugs show up for colloquy, they’re not there to converse, connect, learn, understand or listen. They’re in it to dominate. Winning is all, truth irrelevant. This is bad faith, the malware that corrupts civics.

The result is fake "debates” and "conversations.” They typically descend into belligerent whataboutism. I lied? Well, what about all those lies your people told? The merit of any argument becomes irrelevant. The only thing that counts is the ammo the thugs can fire ad hominem — "at the person” across from them — and the artillery cover they get from their mob.

Whataboutism and other forms of verbal thuggishness are hardly a recent invention. They were already a major theme in the Socratic dialogues (at that time the so-called Sophists were the rhetorical thugs) and then in the trial that ended in a jury of 500 Athenians condemning Socrates to death.

But modern media have made the pathogen more virulent. In the U.S., Fox News and its clones on talk radio and TV in effect honed and perfected verbal thuggishness over decades. Social media picked up the baton. Twitter threads routinely deteriorate into digital shouting matches and name-calling. If last century’s Brownshirts or Blackshirts bludgeoned people, modern trolls "cancel” or "doxx” their victims.

Verbal thuggishness is problematic for two reasons. The first is that atmospherics matter. When thugs or their leaders prime a mob long enough with truculent rhetoric, the violence can easily turn physical. The result is outrages such as the attack on the U.S. Capitol on Jan. 6, 2021.

The second reason is that verbal thuggishness is a form of "epistemic vice.” Rather as bad money drives out good, it displaces "epistemic virtue,” a term academics use to refer to intellectual humility — the ability to recognize our cognitive limits, to admit when we’re wrong, to change or adjust our opinions, to keep our minds open.

What happens when thugs take over — as in Weimar Germany — is that civil people get scared and retreat into their private spheres, leaving the public square to the ruffians. The public and epistemic virtues that America’s Founding Fathers cared so deeply about wane; the vices wax. Symptoms include the spread of conspiracy theories and a cynical disdain for truth. The only value left is power.

If thuggishness is a virus that compromises the operating systems of open societies, is there an anti-malware patch? Not really, I fear. Our only defenses are our holdouts of civility.

People who are reasonable and intellectually humble — "virtuous” — may still be in the numerical majority. But they’re too often inaudible. For democracy and peace to have a chance, they must start voting with their behavior — swaying TV ratings, rejecting lies and manipulations and more. The thugs must start losing. History suggests these struggles can go either way.

Andreas Kluth is a Bloomberg Opinion columnist covering European politics. He is author of "Hannibal and Me.”