Critics perceive Sessions, and the president he serves, as more interested in protecting the police than public safety—a quality often attributed to the larger Republican Party. But even heavily Democratic areas have mixed track records when it comes to addressing police misconduct. That includes California, which is one of the country’s most liberal states but home to some of its deadliest police. Both California’s reforms and shortcomings are worth examining during the Trump era, as activists and researchers consider state-level measures to counter possible federal inaction.

One policy currently being debated among police-reform advocates is the adoption of a statute that would allow state attorneys general to investigate and mandate structural changes within troubled departments, just as the federal Justice Department can. These changes can vary, but could include amending a department’s use-of-force policy or requiring bias training. The proposal has its origins in California, as it is the only state in the country that explicitly authorizes its attorney general to intervene in this way.

William Lockyer was the first California attorney general to exercise that power, after four Riverside police officers shot and killed a 19-year-old black woman in 1998. The shooting ignited community protests and attracted attention from civil-rights activists Al Sharpton and Jesse Jackson. The Riverside County district attorney invited Lockyer to review the evidence and circumstances of the case.

Though the state did not have enough to bring criminal charges against the officers, Lockyer told me, he launched a civil-rights investigation into the Riverside Police Department’s policies and practices. In 2001, he filed a judgment forcing the department to implement specific reforms within a five-year period. The changes included using more experienced officers on overnight shifts and implementing community policing: assigning officers to monitor specific neighborhoods on a long-term basis and build trust with residents.

“The police chief and many others said after the fact that this was the best thing to ever happen to the Riverside Police Department; it really professionalized the force,” Lockyer said. “I think it makes sense to have some external review, whether federal or state, as a way to check local politics and pressures that can stand in the way of reform.”

The Riverside reform agreement presents one case study to examine stronger state intervention in local policing, but state oversight is not an easy fix. The California attorney general has had intervention authority for 16 years, but has only used it a handful of times. That includes investigations launched in December 2016 by then-state attorney general and current U.S. Senator Kamala Harris. Even police-reform researchers who say these statutes have potential acknowledge they can run into problems when it comes to execution.