579 U.S. 232 (2016)
Utah v. Strieff is a major Fourth Amendment case refining the contours of the exclusionary rule's attenuation doctrine.
When an officer unlawfully stops a suspect without reasonable suspicion but then discovers an outstanding arrest warrant, does the warrant attenuate the connection between the illegal stop and the evidence found in a subsequent search incident to arrest, such that the evidence is admissible under the Fourth Amendment?
Under the Fourth Amendment's exclusionary rule and the attenuation doctrine, evidence that is the product of an unlawful search or seizure may nonetheless be admissible if the connection between the unconstitutional police conduct and the discovery of the evidence is sufficiently attenuated. Courts apply the Brown v. Illinois factors to assess attenuation: (1) temporal proximity between the illegality and the acquisition of the evidence; (2) the presence of intervening circumstances; and (3) the purpose and flagrancy of the official misconduct. The discovery of a valid, pre-existing outstanding arrest warrant is a significant intervening circumstance that can break the causal chain and render resulting evidence admissible, particularly where the police misconduct is not purposeful or flagrant.
Yes. The discovery of a valid, pre-existing arrest warrant constituted an intervening circumstance that attenuated the connection between the unconstitutional stop and the evidence seized incident to the arrest. The evidence was admissible, and the Utah Supreme Court's judgment was reversed.
Strieff is a cornerstone attenuation case for criminal procedure. It operationalizes the Brown factors in the ubiquitous practice of warrant checks following stops and clarifies that a valid, pre-existing warrant is a powerful intervening circumstance. The decision narrows the reach of the exclusionary rule in this recurrent setting and highlights the Court's modern trend of limiting suppression in favor of case-specific deterrence analysis. For students, Strieff illustrates the interplay among the exclusionary rule, fruit-of-the-poisonous-tree doctrine, search-incident-to-arrest authority, and the practical realities of policing. The case also foregrounds policy concerns: how attenuation affects police incentives; the consequences for communities with large numbers of minor outstanding warrants; and the tension between doctrinal administrability and robust Fourth Amendment enforcement. The dissents supply critical counterpoints that often appear on exams and in practice arguments about suppression and deterrence.