Missouri State Troopers in riot gear stand in formation outside the Ferguson Police Department in Ferguson, Missouri, November 24, 2014.

Many questions are already being raised about the grand jury decision not to indict Darren Wilson, the white police officer who shot and killed Michael Brown, an unarmed African-American teenager, in Ferguson, Missouri in August. However, many of those questions will, by necessity, remain unresolved: without hearing the same evidence the jury has heard in closed sessions over the past four months, it’s very hard to assess the soundness of their decision.

What is safe to say about the failure to indict is that it isn’t entirely surprising.  While allegations of police brutality are common in the US, it is extremely rare for them to result in criminal charges—or even disciplinary sanctions.

This is not a new problem. In 1998, Human Rights Watch examined mechanisms for police accountability in 14 large cities. We found that excessive use of force by police officers, including unjustified shootings, severe beatings, fatal chokings, and rough treatment, persisted because of overwhelming barriers to accountability. Those barriers included a “code of silence” among officers, flawed systems of reporting and oversight, and scarcity of meaningful information about trends in abuse. Sixteen years later, the US Department of Justice has increased its investigations into “patterns or practices” of abuse in police departments, in line with our recommendations. But elsewhere, we have seen little momentum towards institutional reform.

The events in Ferguson should serve as a wake-up call to cities, towns, and states across the US to reexamine their records on police brutality and accountability. Reform means, among other steps, better data collection about incidents of excessive use of force by the police, and sharing of that data with the federal government. In many jurisdictions, it may mean establishing effective independent oversight bodies that can cut through local pressures to look the other way in cases of police brutality. And it means reviewing police training, policies, and disciplinary systems to ensure they encourage proper police behavior and sanction abuse.

Law enforcement in Missouri should begin by respecting the public’s right to peaceful protest following the grand jury decision. Law enforcement has a duty to protect citizens from violence like that seen last night—but it must do so without repeating the abuses we have seen in past months, which only fuel further rage and resentment. Missouri recently named the members of a “Ferguson Commission” to examine the social and economic conditions underlying Brown’s killing.  To be effective, it is critical that this review also encompass a comprehensive examination of the law enforcement response to the protests that started in August, as well as the police treatment of the community more broadly. And Missouri should look more deeply at its institutions of justice and police discipline to ensure that going forward, victims of police brutality have “accessible and effective remedies,” as required by international law, to vindicate their rights.