President Trump and his political allies have consistently described American cities as zones of decay and disorder populated by minorities — from his 2016 claim that in “our inner cities, African Americans, Hispanics are living in hell because it’s so dangerous” to Sen. Tom Cotton’s (R-Ark.) recent portrait of an “orgy of violence” that “plunged many American cities into anarchy.” So when Trump saw urban mass protests accompanied by opportunistic looting, he may have expected to benefit from a forceful articulation of the politics of “law and order” like Richard Nixon did more than 50 years ago.

At a rally in Tulsa on Saturday, Trump conjured up the purported violent horrors in the nation’s Democratic-run cities — warning, “The Democrats’ push against our police will drive up crime and drive up costs at levels you’d never believe. Thousands of innocent lives will be lost.”

But this message has largely backfired. Trump’s net approval rating has undergone a sharp dive, and prominent military figures denounced his threat to send troops into cities. The Tulsa rally, his first in months, was under attended.

Why did this political strategy fail today when similar moves worked so well in 1968 and for more than 20 years afterward? In large part, it’s because it is hard to argue for deploying troops in the streets of cities that have become far safer, economically vigorous and socially vibrant.

In 1968, urban America was already in decline. Most cities had been losing population for 20 years as whites fled to suburbia, accompanied by millions of jobs as employers sought non-unionized labor and cheap land. Then in the mid-1960s, incidents of police brutality touched off rioting that led to dozens of deaths and billions of dollars in destroyed property, as civil disorder broke out in cities such as Detroit, Los Angeles, Newark, New York and Philadelphia.

Although these uprisings resulted from racial segregation, discrimination and disinvestment in cities, Nixon’s campaign team ignored these factors. Instead, it made urban decline and civil unrest into symbols of national distress. Nixon tapped into the racial anxieties of what he would soon call the “silent majority,” promising a stronger hand against the urban black and brown people who had risen up. He won the White House in 1968 and went on to a landslide reelection.

In the 20 years that followed, Nixon and then Ronald Reagan could run the same successful political play because cities continued to decline, patterns of residential segregation deepened and crime continued to rise: Homicide rates doubled, property crimes tripled and assaults more than quadrupled. This made it easy for conservatives to target white, suburban voters by propagating a racial mythology of urban decline. They justified white flight as a reasonable response to the prospect of black neighbors, described people of color as unwilling to work and fixated on harmful myths about black criminality.

This was accompanied by a cinematic culture that depicted cities as violent hellscapes that could be pacified only by white men using overwhelming force. This genre included iconic films such as “Dirty Harry” (1971), “Death Wish” (1974), “Escape From New York” (1981) and “RoboCop” (1986).

This social and cultural context led to increasing public approval of harsh measures in the name of fighting crime. One early sign was Nixon’s 1971 announcement of the “war on drugs” and New York’s Rockefeller drug laws of 1973, which greatly expanded criminal penalties for even minor drug possession and use. This “tough on crime” stance and its racially coded language to associate criminality with people of color was pioneered by Republicans, but as crime rates continued to rise, Democrats also advocated a heavier hand for law enforcement.

Aggressive racialized policing in cities led to routinized use of torture to extract confessions in places such as Chicago, and to miscarriages of justice such as the Central Park Five case, in which young black and Latino men were falsely convicted of a 1989 attack and exonerated 13 years later (Donald Trump called for the death penalty to be reinstated after the young men were arrested and continues to insist on their guilt). By the start of the 1990s, prominent criminologists were warning of a generation of young, urban “superpredators” who maimed and killed without remorse and predicting “a bloodbath when these kids grow up.” This fueled increasingly harsh state and federal laws on policing, sentencing and incarceration — most notably the 1994 crime bill, the enforcement of which fell most heavily on young African American and Hispanic men.

The irony was that violent crime had already begun to fall before these laws took effect. After peaking in 1991, homicides dropped for a quarter century, with big cities like New York and Los Angeles recording rates that were 75 to 85 percent lower than at their height. In many cities, the streets became safer than at any time since reliable statistics began to be kept.

Notably, these improvements had less to do with policing and more to do with rising immigration, an aging population and better environmental protection within cities, all of which track with lower levels of crime. Other metrics of urban vitality also showed significant improvement: Cities attracted more new residents, downtown home values and commercial rents rose and metropolitan economies became powerhouses of economic growth.

When television series such as “Seinfeld,” “Friends” and “Sex and the City” premiered and became wildly popular in the 1990s, media critics observed that the shows’ urban settings portended a new public image for cities. The overwhelmingly white casts of these and similar shows presented a decidedly unrepresentative vision of urban America: City populations had stabilized only because immigrant families from places such as Latin America and Asia had joined longtime African American residents to solidify a new urban majority. But nobody could doubt that popular perceptions of the big city had quickly and significantly improved.

By the late 2010s, most of the conditions of the urban crisis had receded (although decidedly not including economic inequality and police violence), and the emergence of gentrification indicated that far from desiring an escape from urban life, people of means, including whites, were eager to make their homes in the nation’s largest metropolises.

This transformed the politics of “law and order.” Black scholars and activists and their allies had long critiqued how racialized ideas about crime in cities had fed deadly policy choices such as militarized police departments and mass incarceration. As cities became more desirable, however, their critiques garnered increasing public support.

Today’s suburbs are far more diverse and politically moderate as well, which has helped reshape our debates about racial justice. The New York City suburb of Westchester County, for example, is barely half non-Hispanic white, and a quarter of the population is foreign born. Many suburban congressional districts now have lopsidedly Democratic partisan voter indexes and liberal Democratic U.S. representatives. Indeed, it was the metropolitan vote of urbanites and suburbanites together that so decisively delivered the House to the Democrats in the 2018 midterm election, and placed control of key governorships and state legislatures into Democratic hands between 2017 and 2019.

Our cities and suburbs look and feel very different than they did in the depths of the urban crisis in the late 1960s. That’s one reason Trump’s attempt to revive the law-and-order playbook of that era has fallen flat, even as he and Attorney General William P. Barr sought to enact scaled-up real-life versions of their movie idols, the dirty cop and the private vigilante.

During the urban crisis era, moviegoers packed theaters to see, and schoolchildren endlessly reenacted, a scene from “Dirty Harry” in which the eponymous rogue cop, .44 magnum in hand, stands over a black suspect and dares him to go for his gun. “You’ve got to ask yourself one question: ‘Do I feel lucky?’ Well, do you, punk?” But after decades of seeing crime fall and conceiving of American cities as vibrant spaces — and in the wake of George Floyd’s killing at the hands of brutal officers and widespread video of police beating and tear-gassing peaceful protesters — it seems that an unmistakable majority of Americans are finding it easier to sympathize with the man on the ground than the one with the badge.