A question for our time in the United States is: How have so many individuals broken free of moorings that once stopped them from an uncontrollable drift into senseless violence and mindless behavior?

The two major events of unmoored mass violence in America recently have been the protests-cum-riots after George Floyd’s killing in May 2020 and the Jan. 6, 2021, attack on the U.S. Capitol.

Running...

Wonder Land: With political protests, crime and personal choices hovering at the edge of madness, perhaps it's time to revisit the 'Broken Windows' policing approach pioneered in the 1990s. Images: AP/Reuters/Getty Images Composite: Mark Kelly The Wall Street Journal Interactive Edition

A question for our time in the United States is: How have so many individuals broken free of moorings that once stopped them from an uncontrollable drift into senseless violence and mindless behavior?

The two major events of unmoored mass violence in America recently have been the protests-cum-riots after George Floyd’s killing in May 2020 and the Jan. 6, 2021, attack on the U.S. Capitol.

Running alongside has been a rise of random homicidal shootings and other violent crimes. Last Friday evening, a man in Harlem threw open a bedroom door and unloaded his Glock pistol at three New York policemen responding to a domestic-disturbance call, killing Jason Rivera, a 22-year-old cop instantly. Another, Wilbert Mora, 27, died days later.

The week before in Harlem, a man walked into a Burger King and shot dead the woman working there. As has become routine, he was caught because footage of him shooting was recorded by surveillance cameras, now almost everywhere, and broadcast on TV to the whole city. But oblivious to the cameras, they just keep killing. In the same week, video cameras helped cops in Los Angeles catch the man who knifed to death Brianna Kupfer, while she was working in a furniture store.

Road rage has been with us for years, but now we have airline rage. The latest: In January, three women allegedly beat and stomped a security officer at JFK airport. Guess what? These ladies from Long Island are now under federal indictment in Brooklyn. The indictment felt obliged to note that “extreme behavior” on airlines is “out of control.”

What isn’t out of control?

Political protest today always hovers at the edge of madness. Set aside the so-called politics of the Jan. 6 Capitol attack. The footage has been shown endlessly, revealing what can only be called the joie de destruction of the intruders, who acted as though rampaging through the Capitol was hardly different than bellowing around a parking lot on game day. Hundreds have been arrested and many, who likely had no serious prior arrests, will now have prison time on their records.

Black Lives Matter was supposed to be behind the summer 2020 protests, but a similarly ecstatic, what-the-hell hoot was evident in the lootings and pitched battles with police.

For most of last year, Portland, Ore., descended into a kind of “Mad Max” state of anarchy, beset by costumed street-fighting gangs.

Time was, even career criminals carried inside their heads some rough calculus of the connection between burglary, armed robbery, murder and the likely time they’d spend behind bars. Today, much violent or even nonviolent personal behavior has become mindless, untethered and unhinged.

The man sentenced to life without parole for killing Ahmaud Arbery thought that carrying a loaded shotgun while chasing a suspected burglar through the streets was going to be . . . exactly what? Safe?

The personal-choice function hasn’t been working well among presumed sophisticates, either. Take Andrew Cuomo. The allegations of smarmy sexual overtures by multiple women occurred after the #MeToo storm had already rained down shame on numerous Cuomo-level celebrities in New York City. Governor, what were you thinking?

Answer: Like the Capitol Hill rioters, the looters, the shooters, the Long Island smackdown ladies, New York’s now ex-governor wasn’t thinking anything. They all just did it.

Relaxed prosecution standards, Covid or human weakness going back to Adam and Eve don’t adequately explain the epidemic of senseless violence and behavior.

The urban crime spike has revived the phrase “broken windows.” The article of that name, published in the Atlantic 40 years ago, deserves a big new readership for what it tells us about the collapse of order. It is far more nuanced about effective policing and less rotely “law and order” than its critics purport.

But the ideas in “Broken Windows” aren’t only about controlling crime in poor neighborhoods. They are about the basics of intact communities, and therefore relevant for a broader U.S. society that has become unwilling to police or fix the broken windows of daily life. The authors, George L. Kelling and James Q. Wilson, described the risks: “Failing to do anything about a score of drunks or a hundred vagrants may destroy an entire community.”

The primary culprits aren’t the perpetrators running wild through a society that has devalued accountability. The blame lies with the adults in the room, the establishment elites, who have so often explained away and validated this behavior.

The persistent erosion of behavioral norms, which are hard to establish, was put in motion by the left but eventually expanded to the right. The 2020 Democratic National Convention said nothing about that summer’s looting, just as some on the right fell into after-the-fact rationalizations for the Capitol riot.

Justifications for convention-smashing behavior are always at the ready today, but the cumulative corrosion of standards—what Kelling and Wilson call “the informal control mechanisms of the community”—is now taking a toll on Americans’ presumptions about the internal stability of their country.

Write henninger@wsj.com.