The list of reforms would grow for years: cultural sensitivity training, community policing, overhauls of officer recruitment and training, new videotaping protections, and citizen oversight boards.
"There have been major strides in improving police departments across the country in the past 30 years," says sociologist Ronald Weitzer at The George Washington University in Washington, D.C. "You'll still find pockets [of corruption] – New Orleans is still quite problematic – but there's clearly progress."
One big challenge is that old perceptions – held by both the public and the police – are slow to die, say Mr. Weitzer and others. And those perceptions, shaped by decades of seething relations between African-American communities and local police departments, are refreshed each time police excesses or missteps leap onto the front pages.
To be sure, the steady drip, drip, drip of episodes disturbing to many Americans, and especially to the black community, keeps trickling out. There was the shooting of Trayvon Martin in Florida last year; local police declined to charge the shooter of the unarmed black teenager. There was the 2011 case of military veteran Kenneth Chamberlain Sr., a black senior citizen, killed by police in his White Plains, N.Y., apartment after the officers' response to a medical alert escalated into a confrontation. And there was the 2009 death of Oscar Grant in Oakland, Calif., killed by a transit police officer on the train platform. In each case the pattern repeats itself: shock, outrage, demonstrations, calls for real change.