History is instructive, not because it offers us a blueprint for how to act in the present but because it can help us ask better questions for the future.

The Lexow Committee undertook the first major investigation into police misconduct in New York City in 1894. At the time, the most common complaint against the police was about “clubbing” — “the routine bludgeoning of citizens by patrolmen armed with nightsticks or blackjacks,” as the historian Marilynn Johnson has written.

The Wickersham Commission, convened to study the criminal justice system and examine the problem of Prohibition enforcement, offered a scathing indictment in 1931, including evidence of brutal interrogation strategies. It put the blame on a lack of professionalism among the police.

After the 1967 urban uprisings, the Kerner Commission found that “police actions were ‘final’ incidents before the outbreak of violence in 12 of the 24 surveyed disorders.” Its report listed a now-familiar set of recommendations, like working to build “community support for law enforcement” and reviewing police operations “in the ghetto, to ensure proper conduct by police officers.”

These commissions didn’t stop the violence; they just served as a kind of counterinsurgent function each time police violence led to protests. Calls for similar reforms were trotted out in response to the brutal police beating of Rodney King in 1991 and the rebellion that followed, and again after the killings of Michael Brown and Eric Garner. The final report of the Obama administration’s President’s Task Force on 21st Century Policing resulted in procedural tweaks like implicit-bias training, police-community listening sessions, slight alterations of use-of-force policies and systems to identify potentially problematic officers early on.