In 2015, the American Civil Liberties Union threatened to sue the city of Chicago over the law enforcement practice known as stop and frisk. Among the ACLU’s concerns were authorities targeting racial minorities disproportionately in violation of their constitutional rights. 

In the interest of preventing the lawsuit, the city reached an agreement with the ACLU in which it would curb its use of the procedure. Three years later, in 2018, a high-ranking elected official called upon the city to embrace the stop and frisk practice once again, claiming that it works when properly applied. Nevertheless, the facts paint a picture that is a bit more complex. 


Since the city’s agreement with the ACLU in 2015, a U.S. magistrate’s report assessing compliance found that, in the first six months of 2016, there were only approximately 54,000 investigatory stops in the city. This represented a dramatic decrease from 2014 and 2015, which saw stops in excess of 1.3 million. 

During that same time period, Chicago also saw a dramatic decrease in violent crime. The number of homicides in 2017 was 650, down from 771 the previous year. However, there is not enough evidence to suggest that curbing stop and frisk policing relates to the decrease or was a contributing cause. 

Furthermore, the same study that found a decline of stop and frisk incidence also demonstrated a continued disparate impact on minority residents. 


The Fourth Amendment of the U.S. Constitution protects citizens from unreasonable searches and seizures by officials of the government, including law enforcement. Therefore, for a stop and frisk to be legal, it must meet constitutional standards for reasonableness. 

In other words, only if authorities have reasonable suspicion of a recent or pending crime can they perform a stop. A frisk can only take place if authorities have reason to believe that the individual has a weapon and poses a danger. 

The Supreme Court rendered a decision in 2015, the same year that the city of Chicago reached its agreement with the ACLU, saying that a stop by law enforcement represents an unreasonable seizure if it lasts longer than it takes to handle the matter. Any evidence obtained after the time needed to complete the stop has elapsed is therefore not admissible in court.