Police arrest a counterprotester on Boston Common after the “free speech” rally on Saturday. (Salwan Georges/The Washington Post)

Police riot squads were an inescapable presence at the recent demonstration against white supremacists at a “free speech” rally in Boston, just as they had been a week earlier in Charlottesville. Soon after the event was cut short and a handful of white supremacists were safely escorted by police to waiting vans, buses approached Boston Common from multiple locations and disgorged a stream of armor-clad, helmeted, baton wielding police officers, dispatched to quell the nonviolent assembly.

This display of police aggression escalated tensions, provoked physical confrontations and netted over 30 arrests. In the aftermath of the rally, protesters were left to wonder: Why had the Boston Police Department protected white supremacists but policed anti-racist demonstrators?

The answer does not necessarily lie in the personal politics of police officers themselves, but rather in the deep historical forces that continue to structure the mission and posture of contemporary police riot squads. That history reveals not only the baked-in hostility of big-city police departments to demonstrations for racial equality, but the ways in which these squads threaten to ignite — rather than prevent — urban violence.

Perhaps surprisingly, today’s riot squads do not date to the major uprisings of the late 1960s, when civil rights and antiwar demonstrations were conflated with criminality and violence. Rather, these paramilitary-style units were created to police the growing black population in cities in the early 1960s at the behest of white residents. As the size and functions of riot squads multiplied across the decades, these elite, specialized police squads could not — and still cannot — be untangled from their original purpose: to impose urban order through the harassment and containment of black people.

Boston’s Tactical Patrol Force (TPF) — the forerunner to the Special Operations unit deployed at Saturday’s demonstration — was first formed in 1962, one of the many tactical squads that proliferated in big-city police departments in the early 1960s. These units were emblematic of the police response to the expanding proportion of urban black residents in the decades after World War II.

In Boston, frightened whites turned to the police for protection from impoverished black residents who were confined to a handful of neighborhoods, including Roxbury, Dorchester and Mattapan. In 1966, for example, the Boston Globe reported that “citizens’ complaints about police protection have been on increase, especially in South Boston,” the staunchly white neighborhood that, a few years later, would serve as home base for the ferocious opposition to school desegregation. Police Commissioner Edmund McNamara assured these residents that the TPF would continue to pursue the goals for which it was first established: to “saturate” neighborhoods “plagued by misconduct,” including, not coincidentally, Roxbury, Dorchester and Mattapan.

The prevailing urban white suspicion and fear of black residents set the agenda for tactical squads like the TPF. While the TPF was styled as a highly specialized cadre of men trained in urban combat, “street crime” — theft, burglary and small-scale morals offenses — was the bread-and-butter work of this elite squad. As black criminologists and neighborhood leaders argued, and as the history of policing in Boston bears out, “street crime” was simply a euphemism for “black crime.”

TPF officers routinely focused on petty black offenses. They conducted intensive field interrogations and searches, and frequently deployed decoy details to entrap black women suspected of engaging in prostitution. One white TPF officer recalled in his memoir that in the late 1960s, he and his partner often “made some good grabs” for handbag snatches, fights and prostitution. By 1974, the TPF’s everyday function was officially clarified as a “selective enforcement group concentrating on the reduction of street crimes,” primarily downtown and in black neighborhoods. “Selective enforcement” was yet another euphemism signaling the TPF’s racially charged priorities.

To be sure, black Bostonians clamored for a better police presence in their neighborhoods, where complaints of crime often went overlooked or ignored. But the militant and aggressive TPF more often terrorized than protected in black neighborhoods. As the majority-white TPF officers patrolled black neighborhoods, they brought with them their military-style training that oriented them to perceive ordinary black residents as the enemy.

This volatile combination of paramilitary tactics directed at poor urban residents invariably produced violence. Black people protested the “armed siege” of the TPF in their neighborhoods, calling for the elimination of the tactical squad and the K-9 unit attached to it. They marched bearing posters asking Boston’s then-mayor Kevin White, “Have you ever had a dog trained to kill and attack your kids?”

While the misnomer of “riot squads” would suggest that tactical police units were formed in response to the national wave of black revolts in Harlem, Watts, Detroit, Roxbury and elsewhere, the squads were actually an important cause of these uprisings, not a response, to them. The 1967 report of the National Advisory Commission on Civil Disorders, or the Kerner Commission, which studied the causes of urban racial unrest, concluded that the deployment of tactical squads was a significant “source of friction” contributing to the hostility many black residents felt toward the police.

Despite the manifestly incendiary and provocative nature of tactical squads, they were enormously popular with politicians, police chiefs and white residents across the political spectrum who increasingly argued that tough, racially charged law-and-order policing was necessary to achieve economic and personal security in the nation’s cities. J. Anthony Lukas writes in Common Ground, his account of the Boston busing crisis, how a liberal white family pressured a TPF captain to assign officers to their gentrifying South End neighborhood to stop the “reign of terror” — namely purse-snatchings and prostitution — in the neighborhood. And when, in 1974, liberal reformist BPD Commissioner Robert diGrazia added a “150-man, city-wide, anti-crime unit” to the TPF, it was one of the rare issues on which he and the Boston Police Patrolmen’s Association — the militant rank-and-file union consistently opposed to reforms such as racially inclusive hiring — agreed.

By 1978, after ongoing protests over TPF brutality, black Bostonians won the dissolution of the tactical squad. But it was a hollow victory. The TPF was replaced with an even stronger tactical force, the Special Operations unit, which boasted, according to one TPF officer, “brand new Harley Davidson motorcycles, new Glock semiautomatics with ultra-penetrating ammunition” and SWAT training.

In Boston today, veteran officers often point to the heavy presence of the TPF in white neighborhoods during the busing crisis to prove the racial neutrality of the squad. But a squad created explicitly to target black residents cannot ultimately be neutral. The TPF’s original mandate to enforce a white social order explains the deep-seated institutional imperative to meet contemporary anti-racist Bostonians with brandished batons and a full complement of riot gear.

Police riot squads are a visually menacing and physically terrifying feature of many contemporary anti-racist protests. As white supremacists gain political momentum, we can be assured of the ongoing participation of these militarized police forces in massive demonstrations. As mayors, police chiefs and residents confront a mobilizing force of white supremacists, we must call on urban leaders to shift these forces away from their historical focus on policing black citizens and instead adopt nonviolent measures of police de-escalation — measures in which anti-racist protesters are not policed as a political problem, but rather protected as valued and necessary defenders of our diverse cities.