Sarah A. Seo argues that the advent of the automobile changed American policing. Millions found themselves face to face with law enforcement in new and often unexpected ways. An ethos of “courtesy” soon developed in response to public concern about this new presence in the lives of law-abiding citizens. But courtesy implied discretion, and discretion has often meant racially disparate treatment, as well as serious erosions of the Fourth Amendment.

Clark Neily zooms in on the case Whren v. United States, which sustained an extraordinarily deferential standard regarding when law officers may search vehicles. He notes that under Whren, police may even be overtly racist in their choice of whom to search; constitutional reasonableness, the Court has said, does not permit inquiries about such matters.

Lars Trautman agrees that automobiles were a big part of the story of police discretion as it developed in the twentieth century. He suggests, however, that the pedestrian stop was also important. Under current Supreme Court doctrine, police may stop pedestrians for a seemingly endless number of “reasonable” causes, allowing them wide discretion to search—or decline to search—anyone. He calls attention to the related developments in pedestrian policing, suggesting that we might have “reached the same destination on foot.”

John Pfaff calls attention to the importance of overcriminalization, particularly with regard to misdemeanors. Unfortunately, Americans experience the criminal justice system in very different ways; particularly for white and upper-class people, courtesy is the norm. But others commonly experience another criminal justice system, one in which only trivially bad conduct may lead, not to a warning, but to a stint in jail, a heavy fine, and a criminal record. The solution, he says, is not to abandon courtesy, but to think carefully about the wide range of misdemeanors we have written into law.