In a decision highly-anticipated by the telecommunications industry, law enforcement, and privacy advocates, the U.S. Supreme Court issued a 5-4 ruling that the government generally cannot obtain mobile phone location information without a warrant. Chief Justice John Roberts authored the majority decision, and each of the four dissenting Justices issued their own separate opinion.

The Court's decision ends years of uncertainty about the legal requirements for telecommunications companies to turn over their customers' location information to the government. For decades, service providers and law enforcement have struggled to apply 50- year-old laws written long before current technology existed.

In resolving inconsistencies among various courts across the country, today's decision holds that customers have a reasonable expectation of privacy in information their communications service providers have about their physical location and movement. Disclosing such information to the government, the Court holds, constitutes a search under the Fourth Amendment to the Constitution and requires the government to first obtain a warrant issued by a court.

The Supreme Court bases its decision on the reality that a mobile device's location history “provides an all-encompassing record of the holder’s whereabouts . . . the timestamped data provides an intimate window into a person’s life, revealing not only his particular movements, but through them his ‘familial, political, professional, religious, and sexual associations.'"

Though the decision provides helpful guidance for the disclosure of location information in some circumstances and sets forth reasoning that may facilitate the analysis of how the law could apply to future technologies, Chief Justice Roberts emphasizes the holding’s limits. It does not address the disclosure of real-time cell tower data, “or call into question conventional surveillance techniques and tools, such as security cameras. . . . Nor do we address other business records that might incidentally reveal location information,” the Chief Justice wrote. “Further, our opinion does not consider other collection techniques involving foreign affairs or national security.”

Despite the limited scope of the holding, the ruling provides welcome certainty to wireless carriers and other communications service providers about when they are required to disclose their customers’ location information. Conflicting decisions from lower courts created difficult situations in which carriers were sometimes unsure about how to handle competing obligations to comply with law enforcement requests and protect their customers’ privacy.