FANS of television shows such as “Law and Order” are familiar with the so-called “exclusionary rule”: when police obtain evidence of a crime through illegal means, the evidence is usually inadmissible in court. This rule, an outgrowth of the Fourth Amendment bar on “unreasonable searches and seizures”, deters police from violating citizens’ constitutional rights when undertaking criminal investigations. But the rule just became something closer to a suggestion: on June 20th, the Supreme Court divided along gender lines in a 5-3 ruling that introduces a loophole in rules for obtaining evidence that were developed more than 50 years ago.

The case, Utah v Strieff, involves a dodgy drug bust. Responding to an anonymous tip that narcotics were being sold out of a house in South Salt Lake City, Utah, detective Doug Fackrell started keeping an eye on the property. He didn’t see much from his unmarked car, but he did notice—in the several hours he spent watching over the course of a week—people visiting the home and then quickly leaving. Without keeping track of how long one such visitor spent at the house, Mr Fackrell decided to stop the man, Edward Strieff, for questioning. The detective discovered, after a colleague ran his name through a database, that Mr Strieff had an open warrant for a traffic violation. Mr Strieff was arrested on the traffic warrant and searched, and Mr Fackrell discovered a baggie of methamphetamine and drug paraphernalia in his pockets. He was then charged with drug possession. Mr Strieff challenged the charges by denying that the evidence against him was obtained lawfully: it is no crime, and should incur no suspicion, to simply walk out of somebody’s house.

The prosecution admitted that Mr Fackrell’s questioning of Mr Strieff was unlawful. But Utah maintained that the evidence collected by the detective did not fall under the exclusionary rule since the arrest warrant “attenuated” the link between the illegal stop and Mr Fackrell’s discovery of the drugs. Both the trial court and appeals court agreed with the state. But Mr Strieff bent the ear of the Utah Supreme Court, which determined that only “a voluntary act of a defendant’s free will (as in a confession or consent to search)” can render the collection of evidence kosher after an illegal stop. Since Mr Strieff did not offer such a voluntary act, the drugs found in his pocket may not be used to convict him of a crime.

On Monday, the three female justices on the United States Supreme Court agreed with Utah’s highest court, but the five men ruled against Mr Strieff. In an opinion written by Justice Clarence Thomas, the court quoted its own sentiment in a 2006 case that “[s]uppression of evidence...has always been our last resort, not our first impulse”. One circumstance in which the exclusionary rule does not apply is when “the connection between unconstitutional police conduct and the evidence...has been interrupted by some intervening circumstance”. Since it was the warrant (not the illegal questioning) that gave rise to the arrest, and since Mr Fackrell was “at most negligent” in questioning the suspect, his “errors in judgment hardly rise to a purposeful or flagrant violation of Mr Strieff’s Fourth Amendment rights”, the court held. The drugs can be used as evidence.

Two biting dissents from Justices Elena Kagan and Sonia Sotomayor took sharp issue with this holding. “Do not be soothed by the opinion’s technical language”, Justice Sotomayor warned. “This case allows the police to stop you on the street, demand your identification, and check it for outstanding traffic warrants—even if you are doing nothing wrong. If the officer discovers a warrant for a fine you forgot to pay, courts will now excuse his illegal stop and will admit into evidence anything he happens to find by searching you after arresting you on the warrant.” The exclusionary rule applies, she wrote, “if an officer breaks into a home and finds a forged check lying around”. That evidence “may not be used to prosecute the homeowner for bank fraud”; the check is “fruit of the poisonous tree” and is therefore inadmissible in court. Likewise, in stopping Mr Strieff, since Mr Fackrell’s “sole purpose was to fish for evidence”, the unlawful nature of the stop taints the evidence obtained during that stop.

This caution, delivered strikingly in the second-person, soon pivoted to a more specific warning to communities of colour. Justice Sotomayor mocked the majority’s claim that Mr Fackrell’s misdeed was “isolated” with “no indication that this unlawful stop was part of any systemic or recurrent police misconduct”. With over 7.8m outstanding warrants in state and federal databases, “the vast majority of which appear to be for minor offenses”, police across America now have millions of pretexts for stopping otherwise suspicionless people and asking them to empty their pockets. “[I]t is no secret”, Justice Sotomayor wrote, citing W.E.B. Du Bois’s “The Souls of Black Folk”, James Baldwin's “The Fire Next Time” and Ta-Nehisi Coates’s “Between the World and Me”, “that people of colour are disproportionate victims of this type of scrutiny. For generations, black and brown parents have given their children ‘the talk’—instructing them never to run down the street; always keep your hands where they can be seen; do not even think of talking back to a stranger—all out of fear of how an officer with a gun will react to them."

The majority’s ruling, in the dissent’s eyes, legitimises “the conduct that produces...double consciousness” and “says that your body is subject to invasion while courts excuse the violation of your rights”. With Strieff, victims of unlawful searches are effectively told, “you are not a citizen of a democracy but the subject of a carceral state, just waiting to be cataloged”. This is strong language, and Justice Sotomayor closed with an allusion to the words Eric Garner uttered 11 times in 2014 while he was suffocating in a police chokehold in New York City: “I can’t breathe”. Episodes like the stop of Mr Strieff are neither “isolated” nor acceptable, Justice Sotomayor concluded: “[T]he countless people who are routinely targeted by police...are the canaries in the coal mine whose deaths, civil and literal, warn us that no one can breathe in this atmosphere. They are the ones who recognize that unlawful police stops corrode all our civil liberties and threaten all our lives”.