But with a confrontational and sometimes messy gale of protests appearing to gain broad support, there is evidence to suggest that the calculus is not always so straightforward. There were scattered incidents of looting and arson during the peak of the Black Lives Matter movement, most notably in Ferguson, Mo., where Michael Brown was killed, and Baltimore, where Freddie Gray died, yet sentiment swung heavily in favor of the movement.
And a separate study, from a three-person team of political and social scientists, found that the Rodney King riots of 1992 helped to mobilize liberal white voters and African-Americans in Los Angeles, leading to a leftward shift in some city policies.
Douglas McLeod, a journalism professor at the University of Wisconsin who studies the impact of news coverage on social movements, said people consumed a wider variety of information today, pointing in particular to social media. This can help to circumvent what he called “several conventions in media coverage of social protest that work against the protesters” — including a tendency to focus on instances of protester violence, even when they’re relatively rare, and to privilege the accounts of those in uniform.
Dr. McLeod said that as videos showing police brutality against black people have appeared relentlessly on social media, they have helped persuade skeptical Americans that an endemic problem exists. “When these things accumulate over time, and we start to see more and more of these images, the evidence starts to become more incontrovertible,” he said.
A youth movement — with broad appeal
The current round of protests is youth-led, and so too, to some degree, is the shift in nationwide sentiment. Millennials and members of Generation Z are far more likely to say they believe the police are prone to racist behavior. And according to a PBS/NPR/Marist College poll last year, members of those generations were more than twice as likely to support reparations for slavery, compared with baby boomers and others in older generations.
A Pew survey in 2018 also found a stark generational divide over whether N.F.L. players were right to kneel in protest of racial inequality. Among millennials and teenagers in Generation Z, more than three in five expressed approval of the protests; among baby boomers and other older Americans, an equally large share said they disapproved.
Similar trends play out specifically among young black people and other people of color, who express a greater desire for sweeping change, and a more unanimous suspicion of the police. In a recent Washington Post/Ipsos poll of African-Americans, among respondents 35 and under, nine out of 10 said they did not trust the police to treat people of all races equally — higher than in any other age group.