Last month, Maryland Gov. Larry Hogan signed legislation to establish a commission to investigate which senior officials in the Baltimore Police Department knew about corruption in the department's now-disbanded Gun Trace Task Force, when they knew about it and what they did -- if anything -- in response.

The commission's creation is just the latest chapter in efforts stretching back for more than a century to address systematic corruption, excessive use of force and other lawless behavior that has plagued some of the nation's most storied police departments. In some cases these investigations have resulted in the creation of permanent civilian oversight or review boards with varying levels of authority over police operations.

The vast majority of these boards and commissions have failed to permanently change the culture of the troubled police departments that they were established to oversee, due in large part to a lack of authority over day-to-day police operations or of a mandate for police forces to implement their recommendations. One particular reform, however, holds the promise of institutionalizing reform throughout a police organization: civilian leadership at the top.

New York City's police force, which is currently led by a civilian who came up through its uniformed ranks, is considered one of the nation's most professional and corruption-free departments. But that wasn't always the case. Its transformation dates back to 1894, when the state Senate launched the first comprehensive investigation of corruption in the department. The Lexow Committee, as the investigating panel was known, revealed just how deeply entrenched the NYPD had become in managing and profiting from the city's vice economy, a level of corruption fed and intensified by a pay-for-promotion system within the ranks.

That investigation led to Theodore Roosevelt being installed as president of the board that oversaw the police department. The future president of the United States took to the job with his customary energy and zeal, effectively functioning as the department's civilian commissioner. Most of Roosevelt's reforms didn't outlast his two-year tenure, but later, as governor of New York, he signed legislation replacing the police board and department chief with a single police commissioner, creating the structure that continues to the present day.

Facing opposition from traditionalists who argue that police forces should have a uniformed chief at the top, only a few jurisdictions outside of New York City have adopted its civilian-commissioner model. But it's one that has often proven reasonably effective. In 1966, long before its latter-day scandals unfolded, Baltimore's police force underwent numerous managerial and personnel reforms under Commissioner Donald Pomerleau, most notably in increasing opportunities for blacks and women. And as Boston's commissioner in the 1970s, Robert di Grazia worked to stamp out corruption and professionalize what one of his successors described as "an old-school department set in its ways."

Commissioners working in a civilian capacity, and informed by their years as sworn officers, are able to take a high-level perspective, maintain a level of objectivity and avoid much of the conflict that uniformed police chiefs often face in having to balance their allegiance between the elected officials who appointed them and the personnel who share the uniform that they wear. Civilian leaders can focus more on strategic decision-making to address the concerns of the community and implement recommended reforms and programs that will improve services and help to reduce the fear of crime. And having the ultimate power over administration and discipline gives them the tools they need to deal with problems in the ranks in a systemic way. "To really improve policing, it requires organizational reform, as opposed to investigating individual citizen complaints," says Samuel Walker, author of the 2005 book The New World of Police Accountability.

The organization of policing in Los Angeles illustrates the difficulty of achieving deep reforms in a fragmented power structure. A five-member Board of Police Commissioners sets the policy agenda and oversees strategic decisions, while a uniformed police chief manages the Los Angeles Police Department's daily operations. The board doesn't possess the authority to impose discipline on LAPD personnel, yet is responsible for oversight of the disciplinary process through a civilian-led inspector general's office. By contrast, individuals who hold the title of police commissioner in Boston, New York City and smaller jurisdictions such as Nassau County, N.Y., are responsible for both administration and discipline, while a uniformed chief handles day-to-day operations and tactical deployments.

The policing crisis the nation is facing calls for a resurgence of true reformers in the Roosevelt mold, civilians who are empowered to act and ready to go against institutional norms. In recent years -- and particularly since the killing in 2014 of an unarmed black man by a white police officer in Ferguson, Mo., ignited nationwide protests -- many have campaigned for local office on the promise of reforming police departments and instituting some form of civilian oversight. While the needle hasn't moved as far as many communities would like for it to, progress has been made through legislation and programs that work to bring more oversight to policing. As the journey continues, community leaders and elected officials should take a look at the benefits of institutionalizing civilian police commissioners as a way to move the needle farther.