The Vermont Supreme Court gave electronic privacy a big boost this morning when it approved restrictions placed upon police when conducting searches of electronic devices.

The case originated when police in Burlington, Vermont were investigating a report of a person applying for credit cards online using someone else's identity. Once the police narrowed the investigation to a street address where they thought the perpetrator might live, they asked a judge to issue a search warrant for “all computers or electronic media” located in the house—even though the house had multiple residents.

The judge issued the search warrant, but was wary about approving such a broad search of computers, iPads, and other devices. So he imposed a number of restrictions on the search, including that the police could only look for evidence relating to the alleged identity theft, had to turn the devices over to a third party to conduct the search, and would not be permitted to prosecute a suspect based upon evidence of other crimes found on the devices.

After obtaining the search warrant, state prosecutors appealed the search restrictions to the Vermont Supreme Court. They argued that under the Fourth Amendment to the United States Constitution, judges must either approve or deny search warrant requests, but may not approve them with conditions.

Because search warrant applications are not contested proceedings (there is no one to argue against issuance of the warrant), the state supreme court asked the ACLU and the state public defense agency to submit amicus briefs opposing the prosecution's arguments. The ACLU, joined by its Vermont affiliate and the Electronic Frontier Foundation in San Francisco, argued that the Fourth Amendment permits judges to tailor search warrants to avoid overly invasive searches.

This morning, the Vermont Supreme Court agreed, concluding that conditions limiting the invasiveness of digital searches "serve legitimate privacy interests."

The decision really addresses two questions: 1) whether judges have ANY ability to limit the invasiveness of digital searches, and 2) whether each of the particular conditions imposed by the trial court that issued the warrant were permissible.

As to the first question, the court held that a judge's authority to limit the invasiveness of a digital search is the same as her authority to limit a physical search. Justice John Dooley, writing for the majority, explained:

A judicial officer might authorize a search of a person, including his pockets, without any particular basis for thinking that evidence will be found in the person's pocket as opposed to elsewhere on his person. But that same officer might permissibly refuse to authorize a search of the person's body cavities based on evidence of similar generality.

In both physical and digital searches, the court held, “the investigatory promise must justify the collateral exposure” of a person's private life.

That's a very important statement for modern privacy. We are pleased that the court recognized that electronic devices like iPhones have incredibly intimate details on them, like who you love and what you’re reading about, thinking about, and listening to.

When it came to the second question—the legitimacy of each of the specific conditions that the trial court imposed upon the search warrant—the Vermont Supreme Court upheld all but one. The sole condition struck by the supreme court was the requirement that the police not use evidence of other, unrelated crimes that might be discovered during the search. “[W]e find this instruction unnecessary for privacy protection and inappropriate,” the decision held, because the search would be conducted by a third party, and the police therefore won't stumble upon evidence of an unrelated crime.

The trial court in this case did some very forward thinking, and borrowed some ideas from electronic discovery methods in civil litigation—things like turning the hard drive images over to a third party data contractor, and having the contractor perform the actual search, to avoid giving the police free reign to view whatever files they like.

Overall, this is a fantastic result for personal privacy. As my colleague Jason Williamson, Staff Attorney at the ACLU’s national Criminal Law Reform Project (which did a lot of the work on this case), put it,

Today's decision affirms important 4th Amendment protections and allows courts to reasonably restrict law enforcement efforts to intrude into the personal lives of ordinary Americans. Too often we’ve seen our courts fall short when it comes to adapting privacy law to modern technologies. Here both the trial court and the supreme court have met the challenge creatively yet solidly in line with common sense and existing offline precedents.

Materials in the case are online here.