The Supreme Court’s decision in Herring v. United States authorizes police to defeat the Fourth Amendment’s protections through a process we call evidence laundering. Evidence laundering occurs when one police officer makes a constitutional mistake when gathering evidence and then passes that evidence along to a second officer, who develops it further and then delivers it to prosecutors for use in a criminal case. The original constitutional taint disappears in the wash.

Courts have allowed evidence laundering in a variety of contexts, from cases involving flawed databases to cases stemming from faulty judgments and communication lapses in law enforcement teams. Courts typically zero in on individual officer behavior, or limit their review to a single incident, rather than considering the entire course of conduct. In so doing, they make visible the individualistic view of police work that is implicit in much of Fourth Amendment doctrine. This atomistic perspective, however, fails to appreciate the realities of modern policing, which depends heavily on teamwork and delegation. At the same time, the increased emphasis on police intentions and on balancing the costs and benefits of exclusion brings our courts into closer alignment with courts elsewhere in the world.