Typically, if law enforcement wants to search you or your property in the U.S., they will need either a warrant or probable cause—at least some evidence of wrongdoing. Those things can be hard to come by, limiting the ability of the police to stop and search people at will. But there is a loophole. What if they simply ask for your permission? This is known as a “consent” search because its constitutionality derives from an individual agreeing to be searched rather than any evidence of criminal activity. This common type of police search is tailor-made to circumvent our Fourth Amendment rights to privacy and is so ineffective at locating criminals that its contributions to public safety—insofar as we can measure the concept—appear nonexistent.
How can this be? Consent searches rose to prominence in the 1980s and 1990s during what has come to be known as America’s tough-on-crime period. During this era, policy makers from the political left and right pushed the criminal justice system in a much more punitive direction. Three-strikes laws were invented, ushering in an ongoing period of mass incarceration, and policing tactics became more aggressive, targeted and centered around illegal drugs. The idea was that, instead of waiting to observe a crime or for a 9-1-1 call, officers should use their time on patrol to proactively look for criminals, stopping and then searching as many motorists as possible to prevent crime from occurring in the first place.
For the many instances where no probable cause could be found, officers were trained to convince motorists to give their consent to be searched. A popular police academy textbook in the 1990s devoted chapters to discretionary searches and the art of getting to yes, in which aspiring officers are told: “Gaining his [the driver’s] cooperation requires that you extend the play-dumb guise that you’ve used already.… You need to decide, finally, whether you want to search the suspect’s vehicle. If you do, you now need to position him emotionally to grant you his permission…..” The Fourth Amendment gives us the right to refuse such requests, but many people are unaware of this right or fear to exercise it. And the police are under no obligation to offer reminders.
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That many of these stops fail to turn up evidence of wrongdoing makes the enterprise a numbers game: if criminals are to be apprehended then a lot of innocent people will have to be stopped, questioned and searched. Consequently, highly discretionary police searches, and the proactive styles of policing they enable, are another example of NIMBYism in American cities. People may wish them upon other neighborhoods, but arerarely pleased if they themselves are stopped and interrogated while driving to work. Even less so if these stops happen repeatedly to them and their friends and family. Even in the country’s most crime-plagued communities, most residents have nothing to do with illegal drugs or violent crime and are simply trying to go about their lives.
Research has recently illuminated just how ineffective highly discretionary searches are at locating criminals. Using police records of over 900,000 searches,we find that consent searches are about 30 percent less likely to locate contraband than searches based on probable cause. Perhaps because of these low hit rates, police agencies that rely heavily on consent searches do more searching overall, but, revealingly, do not find more contraband or make more arrests than agencies that rely on constitutionally constrained searches. Moreover, variation over time in the use of consent searches seems to have no relation to fluctuations in violent crime rates.
We also find that Black motorists are more likely to be subject to a consent search but less likely to be found with contraband than white drivers. This suggests that racial bias may motivate officers to stop and search motorists. The same is true of Terry stops, in which police stop and frisk pedestrians on suspicion of criminal activity. These too areincredibly ineffective atlocating criminals, so much so that in 2013 afederal judge ruled that the New York City Police Department’s widespread use of Terry stops was unconstitutional because contraband discoveries were so rare, and because the department used Terry stops in a racially discriminatory manner.
Police work in the U.S. encompasses a vast range of activities meant to promote public safety, or at least to be appropriate societal reactions to crime. For example, if your house is robbed, you want the police to take the matter seriously even if the likelihood that they will solve the crime—find the robbers, recover stolen items, etc.—is small. Most everyone wants the police to stop drunk drivers. Answering calls for service can be a difficult and often thankless job that virtually everyone expects from the police. However, none of these things require consent searches, even as their cost in wasted time and frayed communities is steep.
Much like freedoms of speech, press and religion, the existence of private spaces beyond the purview of government is a foundation of democracy. Policing that routinely capitalizes on an uninformed or intimidated public to encroach on these spaces erodes these foundations, teaching citizens to be wary of government officials and their intentions.
Fortunately, a growing number of municipalities are rethinking the consent search, often in cooperation with local police departments. In 2012 the city government of Fayetteville, N.C., mandated that while municipal police officers could still use consent searches, they would need to obtain written consent so that motorists would be clear on their rights of refusal. Predictably, the number of consent searches carried out by Fayetteville officers immediately plummeted to almost zero. A number of cities, such as Ann Arbor, Mich., and Minneapolis have moved in a similar direction by banning officers from making traffic stops that are for pretextual reasons unrelated to traffic safety.
Our findings suggest that these reforms should not have a meaningful effect on the police’s ability to recover contraband. Instead they have the potential to reduce negative interactions with law enforcement and protect a fundamental democratic right.
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American