Was that search illegal? Sometimes, Neil Gorsuch ruled that it was

Although Judge Gorsuch has a decidedly conservative record on the bench, by at least one measure — his view of the Fourth Amendment’s protections against unreasonable searches — he has been relatively moderate, according to legal scholars and a review of his rulings.

Orin S. Kerr, a George Washington University law professor who specializes in Fourth Amendment and technology issues, said Judge Gorsuch’s opinions suggested that he was “not a knee-jerk vote for the government.” That is important, Mr. Kerr said, because the Supreme Court has yet to resolve many questions about how the Fourth Amendment applies to 21st-century communications.

“The history of the Fourth Amendment is about physically breaking into houses and taking away papers, and the big question is how do you apply that physical concept to a virtual world,” Mr. Kerr said. “Courts are struggling with that, and there is a lot of wiggle room in how to do it.”

Underscoring how ambiguous constitutional law remains in this area, the Intercept website this week published a leaked version of an F.B.I. operational guide that revealed internal rules for emerging investigative technologies that raise Fourth Amendment issues. For example, the guide tells agents not to introduce in court evidence derived from using so-called Stingray devices to locate cellphones’ owners, adding that their use to find people inside buildings “could be deemed to constitute a search under the Fourth Amendment.”