On Friday, President Trump tweeted “when the looting starts, the shooting starts,” in response to the anti-police protests that erupted in Minneapolis after the police killing of George Floyd. Trump was quoting Miami Police Chief Walter Headley, who coined the rhyme in 1967 during his department’s “hoodlum crackdown.” Trump’s tweets also referred to protesters as “THUGS” who dishonored Floyd’s memory. Twitter flagged the post for violating its rules about “glorifying violence” and, though Trump’s allies have cried foul and the official White House Twitter account reposted the tweet, the history behind this language shows why this is true.

Trump’s response to the justified anger of protesters in Minneapolis at yet another black man killed by the police not only misreads the meaning of the unrest — which is about social justice, not criminality. Even worse, his suggested response encouraging police violence threatens to exacerbate the problem of police brutality and killing of African Americans. That’s what happened in the 1960s, when urban unrest in the face of systemic racism led to expanded police power and decades of violence disproportionately targeting black communities.

There is more to the Headley quote than meets the eye. Headley made the statement in 1967 when he announced a ‘Get Tough’ policy aimed at young black men between the ages of 15 and 21 whom he described as “hoodlums.” Crucially, Headley suggested that such get-tough policies would actually prevent riots. His full quote: “We haven’t had any serious problems with civil uprisings and looting because I’ve let the word filter down that when the looting starts, the shooting starts.”

Headley’s views of the preventive capability of the police force was, to say the least, ill-conceived. Indeed, aggressive and racially discriminatory policing in American cities actively produced — rather than prevented — urban unrest and protest during the 1960s. Of the more than 750 urban revolts in nearly 525 cities between 1963 and 1972, nearly all of them were sparked by an episode of police abuse or harassment. Some of the most well-known were in Harlem in 1964, Watts in 1965, and Newark and Detroit in 1967.

In response to the wave of urban uprisings in 1967, President Lyndon Johnson formed a commission led by Illinois Gov. Otto Kerner, called the National Advisory Commission on Civil Disorders. The Kerner Commission’s goal was to locate the causes behind the unrest that summer. The commission investigated and concluded: “Almost invariably the incident that ignites disorder arises from police action.”

Although the commission noted that the Watts, Harlem, Newark and Detroit uprisings were all sparked by arrests of African Americans by white police officers for minor offenses, it recognized that these were not just reactions to individual incidents. Rather, the role played by police over the years in upholding white supremacy, along with police brutality against African Americans, were the roots of the protests. “Thus, to many Negroes police have come to symbolize white power, white racism, and white repression,” the commission concluded. “And the fact is that many police do reflect and express these white attitudes. The atmosphere of hostility and cynicism is reinforced by a widespread belief among Negroes in the existence of police brutality and in a ‘double standard’ of justice and protection — one for Negroes and one for whites.”

The Kerner Commission recommended reforms to address the ways the police interacted with black communities, including eliminating abrasive practices, increasing adequate police protection of black residents, creating mechanisms for solving citizen grievances, setting policy guidelines to assist police in areas where their conduct created tension and recognizing the need to develop community support for law enforcement.

Yet the police had a very different viewpoint. Almost uniformly, chiefs of police referred to participants in the 1960s uprisings as “hoodlums” and “criminals” with no legitimate demands — something that Trump’s reference to the Minneapolis protesters as “THUGS” unjustly reproduces. As the notorious Los Angeles police chief William Parker responded to questions about police brutality as a central cause of the 1965 Watts uprising, “This is a terribly vicious canard which is used to conceal Negro criminality — to try to prevent the Negro public image from reflecting the criminal activity in which some of the Negroes are engaged, to try to find someone else to blame for their crimes.” Police in New York and Chicago invoked the same message during moments of unrest.

Rather than heeding the diagnosis of the Kerner Commission, police sought to criminalize protest and empower themselves in the wake of unrest. Police officials repeatedly emphasized the need for strong law enforcement as the means to prevent unrest. Parker summarized the lesson of the unrest: “You cannot live without strong law enforcement. If anyone thinks he can, he is wrong.”

Indeed, police officials looked to take advantage of the crisis created by urban unrest, not as an opportunity for self-reflection but as a means to bolster their martial authority. Tom Reddin, who followed Parker as chief of the LAPD, testified before the Kerner Commission about the opportunity for police to grab more power. “If we [police] don’t take advantage of what exists in the United States in 1967, we are crazy, because we are never going to have it so good again.” For Reddin, 1968 would be “the year of the cop. Everything you want you get. And I say I want more, and I should be getting it.”

Less than a year after Headley boasted that the threat of shooting rioters would prevent unrest in Miami, the Liberty City neighborhood in Miami erupted in a week of unrest on Aug. 5, 1968, while the Republican National Convention was in town no less.

One of the causes, according to one report of Miami’s 1968 civil unrest, was “tensions of many years standing between the Miami black community and the Miami police, which had sharply increased in recent months.” Most notably, the Miami police had doubled its use of shotguns and dogs in black neighborhoods and employed an aggressive use of the city’s stop-and-frisk law in the eight months leading up to the uprising.

Their response? More weapons requests to bolster their riot control arsenals. In Miami, the study of the 1968 unrest found that “some of the items they [the police] request seem somewhat more suited for outright war than for riot control.”

Miami was not alone. Detroit Mayor Jerome Cavanagh, to name but one, proposed $9 million to purchase riot-control equipment, including 500,000 rounds of ammunition, 700 shotguns, 1,000 M-1 carbines, 6,000 gas grenades and projectiles, eight armored personnel carriers, flak vests, infrared sniper scopes, 50 scout cars, one helicopter and one airplane.

Police turned to force and rejected the findings of the Kerner Commission. Reddin summed up this police attitude: “As a matter of fact, we preach what the military calls the overkill — kill a butterfly with a sledgehammer — feeling that we would rather over-police, and control, and run the risk of people saying we are doing that. We just do not want to let something get out of control."

But research continued to show that the double move of criminalizing protesters and calling for police repression didn’t work, and in fact, exacerbated the problem. “The greatest failings of this [get-tough] policy are that it creates grievances which can accumulate until they actually cause a riot,” concluded the Miami study.

Indeed, the focus on criminalization and force contributed to future episodes of unrest, most directly in Liberty City in 1968, Miami in 1980 and Los Angeles in 1992. Police departments had gotten more equipment and capacity to repress during the late 1960s and 1970s, and communities of color received more of the same: police repression, use of force and killings.

Bolstering police authority and equipment was not the solution to police violence in the 1960s. Nor is it the solution today, which is why Trump’s tweets are so disturbing.

Instead, the calls from Minneapolis protesters to defund the police present a needed alternative to expanding police authority and one that rightly honors Floyd’s memory.

Celebrating get-tough policing and criminalizing anti-police protest glorifies violence, as Twitter explained in its notice on Trump’s tweet. Understanding this history is essential if we want to prevent it from defining the nature of policing in American cities in the 21st century.