Differential enforcement is a fancy way for saying if you are.... I think of a commission that came out with its final conclusion that if you're black, you're going to be treated more harshly than if you are white, and that's at all levels. In the decision to arrest, police had a lot of discretion to exercise. One of the statistics that they used was about drug charges. The ratio was about 3:1.
On September 25th, 2017. See this statement in context.