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Carpenter v. United States Raises Important Privacy Concerns

In November 2017, the Supreme Court heard oral arguments in the case Carpenter v. United States. Carpenter was charged and convicted for his role in a string of armed robberies occurring mostly in the Detroit area. Investigators identified Carpenter as a suspect and were able to place him near the scene of multiple robberies by obtaining the cell-site location information (“CSLI”) from Carpenter’s cell phone provider.1

CSLI is the information cell phone providers gather each time a customer uses his or her phone to connect to a cell tower. When an individual’s cell phone connects to a tower to receive data or calls/texts, a record is created that identifies which tower the cell phone interacted with, the user’s general proximity to the tower, and what time the interaction was made.2 CSLI is used by cell phone providers for various reasons, and generally is considered confidential information the providers do not share with outside parties.

However, there are instances where providers are forced to convey that information to authorities. The Stored Communications Act allows authorities to obtain what is known as a 2703(d) order. This order authorizes government authorities to compel disclosure of a cell phone providers’ records or information (such as CSLI) if the government can offer “specific and articulable facts” that show there are reasonable grounds to believe such information is relevant to an ongoing criminal investigation.3 The burden of proof for a 2703(d) order is noticeably lower than the burden of proof necessary to obtain a search warrant under the Fourth Amendment. This raises one of the central issues in Carpenter: does the government’s acquisition of CSLI constitute a search under the Fourth Amendment, and thus require the government to obtain a warrant?

Another crucial issue in Carpenter has to do with the “Third Party Doctrine.” The Third Party Doctrine states that the Fourth Amendment does not protect records that are voluntarily shared with a third party. The doctrine sprung to life in a 1976 Supreme Court decision, United States v. Miller. There, the government subpoenaed Miller’s bank in search of evidence that Miller was engaged in fraud. Miller argued that the warrantless search of his bank records constituted a violation of the Fourth Amendment. However, the Court disagreed, finding that the information was voluntarily conveyed to the bank in the ordinary course of business, and as such the government did not violate the Fourth Amendment.4

Carpenter raises a similar third party question: does Carpenter’s conveyance of his CSLI to a third party (his cell phone provider) alleviate any potential Fourth Amendment concerns? In recent years, some have come to question the efficacy of the Third Party Doctrine. In United States v. Jones, a 2012 Supreme Court case, Justice Sonia Sotomayor seemed to suggest that it might be time to get rid of the Third Party Doctrine.5. If the Court does indeed go that far in its ruling, Carpenter could have drastic effects on the way user and customer information is shared with other parties. Combined with the other obvious Fourth Amendment questions at issue in this case, Carpenter has the potential to be one of the most influential cases of the 2017 term.

  1. George Horn, Supreme Court Addresses Cell Phone Privacy in Carpenter v. United States, Lexology (Jan. 2, 2018),

  2. Robinson Meyer, How the Government Surveils Cellphones: A Primer, Atlantic (Sept. 11, 2015),

  3. 18 U.S.C. § 2703 (1986). 

  4. United States v. Miller, 425 U.S. 435 (1976). 

  5. United States v. Jones, 565 U.S. 400 (2012).