Maryland v. King, 569 U.S. 435 (2013)
Maryland v. King is a landmark Fourth Amendment decision addressing whether law enforcement may collect a cheek swab of DNA from individuals arrested for serious offenses without a warrant and use it to check for matches in a national database.
Does the Fourth Amendment permit police, without a warrant and without individualized suspicion, to take and analyze a buccal swab of DNA from an individual arrested for a serious offense as part of the routine booking process?
Under the Fourth Amendment, the reasonableness of a search is assessed by balancing the degree of intrusion on an individual's privacy against the degree to which the search advances legitimate governmental interests. Warrantless, suspicionless searches may be reasonable when conducted as part of routine booking procedures for arrestees with diminished expectations of privacy, particularly when the search is minimally intrusive and serves important governmental interests in identification and safe, informed custodial decisions. A buccal swab taken from an arrestee for a serious offense, analyzed for limited identifying markers and subject to statutory protections, is constitutionally reasonable as part of the booking process.
Yes. Taking and analyzing a cheek swab of DNA from an arrestee for a serious offense is, like fingerprinting and photographing, a legitimate booking procedure that is reasonable under the Fourth Amendment. The Supreme Court reversed the judgment of the Maryland Court of Appeals.
Maryland v. King validates DNA cheek swabs of arrestees for serious offenses as part of routine booking, expanding the scope of permissible suspicionless searches under the Fourth Amendment. It cements a doctrinal analogy between DNA profiling and fingerprinting, grounding reasonableness in a balancing approach rather than a warrant requirement or a narrow "special needs" framework. For law students, the case illustrates modern Fourth Amendment methodology, the interplay between technological change and privacy expectations, and how statutory safeguards can influence constitutional analysis. It also highlights fault lines between the majority's identification rationale and the dissent's crime-control critique—fault lines relevant to emerging debates over biometrics, database searches, and digital privacy.