‘We take the big sellers, you take the small sellers.” It was a sensible division of labor, the kind that needs to be made when the federal and state governments have “concurrent jurisdiction” over a crime category, such as drug-trafficking.

Controlled substances are regulated under the police power that states exercise over their internal affairs. Simultaneously, drugs fall under federal purview, pursuant to penal statutes enacted under Congress’s interstate-commerce authority. In theory, then, any illegal act involving narcotics could be prosecuted by state and federal prosecutors. Since there are many more criminal acts than resources to prosecute them, the feds and …