Buying Data and the Fourth Amendment by Orin S. Kerr

Orin S. Kerr, Buying Data and the Fourth Amendment, Hoover Institution, Aegis Series Paper No. 2109 (Nov. 17, 2021):

In Carpenter v. United States, the Supreme Court held that the Fourth Amendment requires the government to obtain a warrant before compelling a cell phone service provider to disclose at least seven days of a user’s historical cell-site location records. This is a groundbreaking holding. For the first time, users have Fourth Amendment rights in corporate records about them that they did not make, cannot control, and likely do not even know exist.

Carpenter prompts a question: If the Fourth Amendment requires a warrant for the government to compel a provider to hand over records, is the same true if the government buys those records instead? Put another way, if the company is willing to sell the records to the government—or has already sold them to someone else who will sell them to the government—can the government purchase the records without a warrant as an end run around Carpenter?

This essay offers two responses. First, existing law leads to a clear answer: The government can buy business records without a warrant or any cause. The Fourth Amendment does not apply. The reason is that a company will have common authority over business records that it has created and controls. That common authority permits third-party consent. When a company voluntarily sells its business records, its consent renders any search of the records reasonable. Although sales of user communications contents might present a different case, the sale of noncontent business records—what I call “Carpenter-protected records,” as they are business records protected because of Carpenter—is permitted. As a matter of Fourth Amendment law, the company can do what it wants with its records even if users with Fourth Amendment rights oppose it.

The second response is a caveat to the first. Although current doctrine gives a green light to buying Carpenter-protected records, a sea change in how often the government can buy records to conduct detailed surveillance might someday justify a more restrictive approach. This possibility is based on the equilibrium-adjustment principles driving Carpenter. When new technology and social practice threaten to create a privacy dystopia, the argument goes, Fourth Amendment rules may have to be tweaked to restore the traditional balance of government power. This possibility should be more theoretical than real, however, for buying Carpenter-protected data. Based on the public record, the factual basis does not exist for an additional adjustment. Buying records has not become a substitute for the detailed surveillance Carpenter addressed. In my view, meeting the high bar of equilibrium-adjustment would require a seismic shift in government power that has not emerged. For the foreseeable future, the Fourth Amendment law of buying Carpenter-protected databases should be simple. It is allowed.