Are Subway Searches Legal?

The rules for searching bags.

Whatcha got in there?

Police officers began conducting random searches on New York City subways last week. Privacy advocates call the New York Police Department’s new search policy unconstitutional—the executive director of the New York Civil Liberties Union says the group is “looking into litigation.” Is baggage screening on the subway legal?

Depends on how it’s done. The Fourth Amendment protects people from “unreasonable searches or seizures.” As a general rule, the government can’t search your baggage without a reason to believe you’re a criminal. But according to legal precedent, a random search is acceptable if it fulfills special needs like public safety. If New York’s subway screenings are challenged in court, the city’s lawyers could argue that the program’s primary purpose is to protect the city from terrorism.

Unless a judge agrees that they fulfill a special need, the screenings will be on shaky legal ground. In 2000, the Supreme Court ruled that a roadblock used to screen drivers for drug crimes was unconstitutional, since its primary purpose was to apprehend drug traffickers. On the other hand, roadblocks that screen for drunk drivers have been deemed OK, since they promote highway safety. (The court did say in the 2000 ruling that “a roadblock set up to thwart an imminent terrorist attack” would almost certainly be constitutional.)

If the subway searches pass this first test, the courts will also ask if there is adequate justification for the invasion of privacy. Are the searches effective? Do they address a real danger? Do they maintain a proper balance between the individual’s freedoms of property and movement?

Before last year’s Republican National Convention, a judge ruled against the NYPD’s policy of checking bags at protests. Another court rejected the use of metal detectors at a protest in Georgia, arguing that general concern over terrorism is not a sufficient basis for an unprovoked search. (In both of these cases, the protesters were able to invoke freedom of speech protections; subway riders in New York can’t make that case.)

Let’s assume the courts believe the subways searches are an effective deterrent for terrorism and that the recent subway bombings in London make them reasonable. Then a judge would have to consider whether the scope and duration of the searches is appropriate. The first random subway screenings occurred last summer in Boston during the Democratic Convention. A district court ruled that searches on trains that ran beneath the convention center were acceptable since they took place in a restricted area for a limited amount of time. The New York City searches, though, are taking place all over the system and seem to be of open-ended duration.

The judge must also consider how individuals are selected for screening. If police officers have too much discretion, they might single out certain kinds of people for “random” searches. To prevent profiling, cops are sometimes given a strict formula—in Boston, for example, every 11th passenger was pulled aside at some commuter rail stations. The NYPD says “numerical criteria” are being used, but spokesmen also say that large or suspicious-looking bags can be red flags.

Bonus Explainer: How are airport screenings different from subway screenings? Since airports screen every passenger to some degree, there’s less risk of an officer having too much discretion. Also, air travel is generally considered one of several options that a traveler might have—if they don’t want to be searched, they can drive or take the bus. New York City officials have suggested that subway screenings are consensual. At least for now, they’re being conducted outside the turnstiles, and those who refuse to participate can choose another mode of transportation. Privacy advocates argue that many New Yorkers don’t have other transportation choices—they need the subway to get to work.

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Explainer thanks Tracey Maclin of Boston University, Urszula Masny-Latos of the National Lawyers Guild, and Andrew Taslitz of Howard University.