Does a search warrant ordering Google to give law enforcement information regarding internet searches containing specific keywords made during a particular window of time violate the Fourth Amendment? This question was before the Colorado Supreme Court in 2023 and is now before the Pennsylvania Supreme Court. The Fourth Amendment protects against unreasonable searches and seizures by the government. The government generally needs a warrant to perform a search that infringes a reasonable expectation of privacy. To guard against misuse of government investigative power, the Fourth Amendment provides that search warrants can only be issued “upon probable cause” and that they must describe with particularity “the place to be searched, and the persons or things to be seized.” Probable cause and particularity in light of 21st century investigative technologies, such as keyword searches, raise novel and important questions that courts have only recently begun to consider. While Colorado and Pennsylvania appear to be the first states where the state’s highest court is considering the constitutionality of keyword search warrants, the power of this investigative technique guarantees that this issue will reach other state supreme courts as well. At root is the question of whether keyword search warrants are general warrants, and thus by definition unconstitutional. 

[John Villasenor is a nonresident senior fellow in Governance Studies and the Center for Technology Innovation at Brookings. He is also a professor of electrical engineering, law, public policy, and management at UCLA, as well as co-director of the UCLA Institute for Technology, Law, and Policy.]