Calvetta Williams, founder of Mothers Against Violence in Des Moines, Iowa, is all about peaceful protest. She organized a march through the city Saturday that began and ended without a hint of violence. Yet, one day earlier, as the 49-year-old watched people smash windows in a haze of tear gas, she understood the frustration and rage that caused some to lash out. "I'm angry, too," Williams said. "I'm a black mother with two black sons, and I'm tired of using hashtags with the names of people murdered by police officers...
