Shortly after a St. Louis County grand jury decided not to indict white police officer Darren Wilson for shooting and killing unarmed black teenager Michael Brown in Ferguson, Missouri, Attorney General Eric Holder issued a statement condoning non-violent protest against the decision but condemning acts of vandalism. Holder’s remarks distinguished between “legitimate demonstrators” and those who “were trying to loot and trying to destroy businesses and burn things.”

“The way in which we have made progress in this country is when we have seen peaceful, nonviolent demonstrations that have led to the change that has been the most long-lasting and the most pervasive,” he said.

President Barack Obama and St. Louis County prosecutor Bob McCulloch, among others, expressed similar sentiments. The president declared that justice could not be achieved by using anger at the Michael Brown verdict “as an excuse to vandalize property,” while McCulloch urged protesters to “keep that discussion going” but to “do it in a constructive way.”

Obama's desire to avoid the destruction of lives and property is hardly surprising, and is widely shared on all sides of the divide over the Michael Brown verdict. But the idea that the historical record shows that exclusively non-violent protest has driven progressive social change in America is open to question. In a number of cases, the crisis caused by riots and property destruction has had a significant role in forcing authorities to respond to demands for political change. And even some of America’s most iconic “nonviolent” movements included moments of destruction and chaos not unlike that which occurred in Ferguson following the grand jury decision.

Many of those criticizing destructive behavior in Ferguson over the past week have cited the example of Dr. Martin Luther King, Jr. and the civil rights movement of the 1950s and 60s as the model for nonviolent, orderly resistance. Peaceful demonstrations — sometimes in the face of violent policing and provocation — were certainly a key feature of the civil rights era. So, too, were outbreaks of violence such as the 1965 Watts Riots in Los Angeles.

While Dr. King never advocated violent and destructive behavior, he also said it would be “morally irresponsible” to condemn riots “without, at the same time, condemning the contingent, intolerable conditions that exist in our society.”

“These conditions are the things that cause individuals to feel that they have no other alternative than to engage in violent rebellions to get attention,” King said in a 1968 speech. “And I must say tonight that a riot is the language of the unheard.”

Nor has it only been the victims of the Jim Crow period that have spoken in that language. The modern gay-rights movement may have won many of its recent victories at the ballot box and in the courthouse, but it was born out of an act of violent desperation when a 1969 raid a New York City gay bar, the Stonewall Inn, turned into a riot as crowds attacked the police. Today, its June 28 anniversary is celebrated annually as Gay Pride Day, and President Obama in his second inaugural speech hailed Stonewall — along with Seneca Falls (birthplace of the movement for women's rights) and civil rights marches in Selma — as milestones on America's journey to realize the dream of equality.

The battle for the eight-hour working day in the U.S. included such violent outbursts as the 1886 Haymarket riot, while a key moment in the fight for labor's right to organize trade unions came at the 1921 Battle of Blair Mountain, when thousands of striking coal miners waged open warfare on local law enforcement and the U.S. military. “Food riots” were also common throughout the U.S. during the Great Depression, fueling the social crisis that spurred the New Deal.

History offers no definitive judgment on whether these acts of violence were productive. Social movements, after all, are diffuse and complicated, and the social and political change that emerges from moments of great upheaval can rarely be attributed to any single cause. But once society has embraced changes driven by social movements, the more unpleasant and uncomfortable aspects of their history is often forgotten.

It's worth noting the advice of social scientists to avoid a simple distinction between "legitimate" movements and violent upheavals in studying the history of protest driving social change in the U.S. Writing of the civil rights movement, Stanford sociologist Doug McAdam offers an analysis that may apply more broadly: It was, he wrote, “a coalition of thousands of local efforts nationwide, spanning several decades, hundreds of discrete groups, and all manner of strategies and tactics—legal, illegal, institutional, non-institutional, violent, non-violent.”

But what shaped the place of all social movements in U.S. history was ultimately how the authorities responded to the grievances that brought the complainants out onto the streets in the first place.