You can read the full ruling here.
Your mobile carrier captures and stores that information, and law enforcement agencies want access to it to catch and convict bad guys. With the appeals court ruling, now investigators don't even have to get a warrant from a court before knocking on the door of your wireless provider's server room. The big concern is that this amounts to a systematic violation of the privacy and security rights of Americans who have done nothing wrong, and aren't suspects, or shouldn't be considered suspects.
The 4th U.S. Circuit Court of Appeals in Richmond, Virginia voted 12-3 that the government may get cellphone data, because of a decades-old legal theory that you have already willingly shared this data to a third party—-your mobile service provider.
The U.S. Justice Department has not yet commented on the decision.
The ruling overturns a divided 2015 opinion from the court's three-judge panel and reduces the likelihood that the Supreme Court would consider the issue. The decision arose from several armed robberies in Baltimore and Baltimore County, Maryland, in early 2011, leading to the convictions of Aaron Graham and Eric Jordan.
The convictions were based in part on 221 days of cellphone data investigators obtained from wireless provider Sprint, which included about 29,000 location records for the defendants, according to the appeals court opinion.
Writing for the majority, Judge Diana Motz said obtaining cell-site information did not violate the protection against unreasonable searches found in the Fourth Amendment of the U.S. Constitution because cellphone users are generally aware that they are voluntarily sharing such data with their provider.
"Anyone who has stepped outside to 'get a signal,' or has warned a caller of a potential loss of service before entering an elevator, understands, on some level, that location matters," Motz wrote.
The battle over how much secret location-data surveillance the government should be able to do on American citizens is elsewhere in the news this week, too. As Verge reports in this video, U.S. police are filing warrants for Android’s vast store of location data.
At Reason, Scott Shackford offers this take on the Virginia appeals court ruling.
This ruling may end up preserving the status quo. There have been several cases challenging the idea that phone location data should count as a third-party record, but so far courts have been upholding the precedent (eventually in this case, since a smaller panel initially ruled otherwise). Typically, the Supreme Court will take on a case like this when there are split rulings between federal courts. That's not the situation at the moment. However, in United States v. Jones, a case from 2012 where the Supreme Court ruled that law enforcement must get a warrant to place a GPS tracker on a vehicle, Justice Sonia Sotomayor said in a concurrent opinion that it may be time for the Supreme Court to reconsider or re-evaluate when the third-party doctrine should apply in this new digital age.
In the dissenting opinion in this case, which involved authorities collecting more than 200 days of data and close to 30,000 locations, Judge James Wynn questioned whether all this information was actually "voluntarily conveyed” to third parties. He points out that previous third-party doctrine rulings were based on the idea that a person, for example called a phone number (thus giving the phone company the information about who he wanted to talk to) or deposited money in a bank (thus voluntarily giving the bank information about the transaction). By contrast, we now give out information about ourselves just by having the cellphone on us, without doing anything at all.
From the opinion of the dissenting Judge Wynn:
"[T]here is no reason to think that a cell phone user is aware of his CSLI [cell-site location information], or that he is conveying it. He does not write it down on a piece of paper, like the dollar amount on a deposit slip, or enter it into a device, as he does a phone number before placing a call. Nor does CSLI subsequently appear on a cell phone customer's statement. …
In sum, because a cell phone customer neither possesses knowledge of his CSLI nor acts to disclose it, I agree with the Third Circuit that he "has not ‘voluntarily' shared his location information with a cellular provider in any meaningful way.”
"What this elucidates is the extraordinary breadth of the majority's decision today. It is not bounded by the relative precision of location data, by the frequency with which it is collected, or by the statutory safeguards Congress has thought it prudent to enact. The majority's holding, under the guise of humble service to Supreme Court precedent, markedly advances the frontlines of the third-party doctrine. The Fourth Amendment, necessarily, is in retreat."
On the side of your data privacy and security rights in this case, as listed in the court documents, are the following organizations:
ELECTRONIC FRONTIER FOUNDATION; NATIONAL ASSOCIATION OF CRIMINAL DEFENSE LAWYERS; AMERICAN CIVIL LIBERTIES UNION FOUNDATION OF MARYLAND; CENTER FOR DEMOCRACY & TECHNOLOGY; AMERICAN CIVIL LIBERTIES UNION FOUNDATION; DOWNSIZEDC.ORG; DOWNSIZE DC FOUNDATION; GUN OWNERS FOUNDATION; GUN OWNERS OF AMERICA, INC.; INSTITUTE ON THE CONSTITUTION; REPORTERS COMMITTEE FOR FREEDOM OF THE PRESS.
You can support the EFF and get involved here.