There was a Monty Python quality to the oral arguments on Wednesday in the two Supreme Court cases involving drug-sniffing dogs. The lawyer who was challenging the use of dogs to sniff on a suspect’s front porch without a warrant said, “whether it’s a Cockapoo or Franky, who from all the pictures appears to be a very cute dog, it’s not what the dog looks like, it’s what the dog is doing on the front porch.” But despite the many dog jokes at the oral arguments and in the briefs (which note that Frank, the drug sniffing Labrador retriever “is currently enjoying retirement as the family pet for his handler in Miami-Dade County Florida”) the stakes in the two cases could hardly be higher: they involve nothing less than the question of how closely the Court is willing to scrutinize the invasiveness and effectiveness of privacy-invading tools designed to detect contraband--not only drug-sniffing dogs on front porches but also naked bodyscanners at airports and spectrascopes designed to detect drugs on the street.

It was encouraging that, in the first case, Florida v. Jardines, the conservative justices seemed receptive to the idea that, because people have property interests in the curtilage surrounding their homes, the police couldn’t take a dog onto a suspect’s front porch to sniff for drugs. “I think you cannot enter the protected portion of a home, which is called the curtilage, with the intention of conducting a search, that is not permitted,” said Justice Antonin Scalia. But Scalia’s emphasis on protecting privacy by enforcing the laws of private property—which he also emphasized last term in striking down the police’s decision to affix a GPS device on a suspect’s car without consent—provides little protection for privacy at a time when most of the threats we experience come not from drug-sniffing dogs on our porches but from technologies that can scan our naked bodies in airports or scan the content of our papers and emails stored on third-party servers in the digital cloud.

That’s why the question posed by second case, Florida v. Harris, was even more important, although it received less attention: should courts independently evaluate the accuracy of dog sniffs by reviewing not only their training but their overall rate of false alerts. Unfortunately, judicial review of the accuracy and intrusiveness of privacy-invading technologies outside the home is something the conservative justices seemed less inclined to encourage.

Ever since 1983, the Supreme Court has treated specially trained narcotics dogs as a kind of perfect search. Because they’re trained only to reveal the presence or absence of drugs or contraband, and don’t reveal any innocent or embarrassing property or activity, the Court held, dog sniffs don’t threaten any legitimate privacy interests or require warrants or probable cause at all. If a technology truly is completely effective and minimally intrusive—in other words, if it actually revealed only drugs and nothing else -- the Court is right that it should be upheld as a completely reasonable search. Unfortunately, lots of evidence since 1983 has suggested that dogs often falsely alert depending on their training, or on the subtle “cuing” of their police-masters: Justice Sonia Sotomayor was especially troubled by an Australian study showing that “one dog alerted correctly only 12 percent of the time.”

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