In June 2015, a white supremacist opened fire inside the historic African Methodist Episcopal Church in Charleston, South Carolina, killing nine black congregants, including the minister. The massacre sparked a crescendo of anti-racist protest, including often successful demands for the removal of statues of Confederate Generals from public spaces throughout the South.

Two years later, a coalition of white nationalists arrived in Charlottesville, Virginia, for a “Unite the Right” rally aimed at protesting and reversing the local City Council’s decision to remove from the city’s center of a hundred year-old statue of Confederate General Robert E. Lee.

Also gathered in Charlottesville were civil rights activists who sought to support the city’s resolve in removing the statue, and to press for further reforms aimed at dismantling institutional white supremacy. The event turned violent after the white nationalists attacked the racial justice advocates with tiki torches, pepper spray and lighter fluid. Fights erupted, injuring at least 30 people. The weekend of protest ended when one of the white nationalists deliberately rammed his car into a crowd of antiracist counter-protesters, injuring 19 and killing one. Refusing to condemn either the goals or the actions of the white nationalists, President Trump commented that there were “very bad people … and very fine people on both sides.”

Trump was correct about that. In this encounter between white nationalists and civil rights activists, there were undoubtedly good individuals and bad individuals on both sides. How, then, can we judge which movement was the “good” one and which the “bad?”

The answer can be found in the sociological study of social movements. Over decades of focused research, the field has demonstrated that evaluating the moral compass of individual participants does little to advance our understanding of the morality or the actions of a large movement. Only by assessing the goals, tactics and outcomes of movements as collective phenomena can we begin to discern the distinction between “good” and “bad” movements.

Modern social movement theory developed from foundational studies by several generations of scholars, notably W.E.B. DuBois, Ida B. Wells, C.L.R. James, E.P. Thompson, Eric Hobsbawm, Charles Tilly and Howard Zinn. Their works analyzing “large” historical processes provided later social scientists with three working propositions.

First, the morality of a movement is measured by the type of change it seeks. “Good” movements are emancipatory: they seek to pressure institutional authorities into reducing systemic inequality, extending democratic rights to previously excluded groups, and alleviating material, social, and political injustices. “Bad” movements tend to be reactionary. They arise in response to good movements and they seek to preserve or intensify the exclusionary structures, laws and policies that the emancipatory movements are challenging.

Second, large-scale institutional changes that broaden freedom or advance the cause of social justice are rarely initiated by institutional authorities or political elites. Rather, most social progress is the result of pressure exerted from the bottom up, by ordinary people who press for reform by engaging in collective and creative disorders outside the bounds of mainstream institutions.

And third, good intentions—aspiring to achieve emancipatory goals—by no means guarantee that a movement will succeed.

The highly popular and emancipatory protests of the 1960s, as well as the influence of groundbreaking works in social history mentioned above, inspired a renaissance in the study of social movements in subsequent decades. Focusing primarily on “good” movements, a new generation of social scientists sought to identify the environmental circumstances, organizational features and strategic choices that increased the likelihood that “good intentions” would translate into tangible change. This research has generated a rich trove of findings:

Successful movements must define their goals clearly and target the institutions that have the power to make the changes they are demanding.

Successful movements should act in a political environment in which they have leverage to demand systemic change. Authorities who control institutional policy grant concessions only when organized disruptions are more damaging to their continued power than giving in to the demands of the movement.

Successful movements must include the rank and file of the constituencies they are representing in decisions concerning goals and tactics. Often this involves working in tandem with organizations that link the movement to the communities that will benefit from the movement’s success.

Successful movements should cultivate “conscience” constituencies—sympathizers, celebrities, patrons—who may not directly benefit from the movement’s goals but are willing to contribute money, facilities, equipment, access to media and other resources.

Successful movements cannot be “greedy.” They must recognize and respect members’ private lives and personal obligations, prepare participants for the dangers and risks of each protest, and allow each individual to choose—without coercion—which actions they are willing to take.

Successful movements generate the solidarity needed to undertake collective action by creating an active and supportive internal life and culture among their participants. The internal life of a movement should prefigure the emancipatory changes sought in the broader society. It should offer interactional and decision-making opportunities not available outside the movement, including social and cultural events that are enriching and fun, and which build the mutual trust necessary for sustaining collective action

Successful movements must anticipate repression, including stand-offs with institutional authorities, forcible dispersal by police, confrontations with counter-protesters, long-term interference from intelligence agencies, and mass arrests.

Successful movements implement processes that allow for effective collective responses to repression–including strategic retreat, enduring repression, active confrontation, and escalation of protest.

And still, there are no guarantees of success. Because social movements form organically, outside of mainstream institutions, they are by nature messy. Rarely does meaningful change happen by relying exclusively on peaceful and lawful means. Petitions, marches, litigation, and chanting are only part of the protest repertoire. Achieving systemic change invariably requires creating disorder: social movements gain leverage when they disrupt business-as-usual for the institution they are targeting—by stopping traffic, blocking commerce, surrounding buildings or interfering with administrative activities. Generations of activists, as well as the scholars who study social movements, have been challenged by the need to deploy effective strategies when nonviolent disruption reaches an impasse without generating concessionary responses; or when it provokes violent responses by the police or by counterdemonstrators aimed at defeating the demands for institutional change.

Faced with severe repression, good movements typically retreat. But dispersing a disruptive action can often guarantee failure, because the movement may not have the capacity to rebuild its strength and recapture the leverage. The alternative is to hold their ground, facing off with police or counterdemonstrators, thus prolonging and intensifying the disruption. The police and counterdemonstrators, who aim to dismantle the protest, must therefore target the bodies of activists. The human casualties that can occur on both sides can, in an instant, transform a site of protest into a sensationalized event, drawing attention away from the political aims of the movement.

Sites of protest are thus both vibrant and vulnerable. But social movements that are attempting to ameliorate “big” social problems and gaping contradictions in the democratic order—economic inequities, racism, patriarchy—are long-term processes. As such, the clash between white supremacists and racial justice activists that took place in Charlottesville in 2017 should be viewed as a recent “moment” in the long civil rights movement that began at the end of the Civil War. Persistence—sustaining commitment, perhaps over the course of a lifetime; expanding networks while forming and reforming coalitions; assessing failures and devising new strategies; exploiting new political opportunities with fresh tactical repertoires; and integrating new generations into the life of the movement—is key to assuring further moments of success. As the pioneers of social history have shown, this is how “bad” movements are defeated and “good” changes are won.

This is an opinion and analysis article.