Master The Supreme Court held that warrantless breath tests are permissible incident to DUI arrests, but warrantless blood tests generally are not, limiting states’ ability to criminalize refusal of blood tests. with this comprehensive case brief.
Birchfield v. North Dakota is a landmark Fourth Amendment decision delineating the constitutional boundaries of compelled chemical testing in drunk-driving enforcement. The Court confronted the modern interplay between DUI policing, implied-consent regimes, and the search-incident-to-arrest exception. Recognizing the strong governmental interest in combating impaired driving, the Court nonetheless drew a constitutional line between two common investigative techniques: breath tests and blood tests.
By holding that breath tests may be conducted without a warrant as a valid search incident to a lawful arrest, while blood tests generally require a warrant, the Court clarified the extent to which states can impose criminal penalties for test refusal. The decision reshaped implied-consent laws nationwide, permitting criminal penalties for refusing breath tests but not for refusing blood tests, and underscored that consent must be voluntary—rather than coercively obtained by threat of unlawful penalties.
Birchfield v. North Dakota, 579 U.S. 438 (2016) (U.S. Supreme Court)
The Supreme Court consolidated three cases arising from state laws that criminalized refusal to submit to chemical testing after arrest for driving under the influence. In North Dakota, Danny Birchfield was arrested for suspected DUI after failing field sobriety tests. When an officer demanded a blood test and warned that refusal was a crime, Birchfield refused and was convicted of the standalone offense of refusal to submit to a blood test. In Minnesota, William Bernard was arrested on probable cause for DUI and declined to take a breath test at the station; he was charged with criminal test refusal under a Minnesota statute. In a second North Dakota case, Steven Beylund agreed to a warrantless blood draw after being told that refusal itself was a crime; the test showed an unlawful blood-alcohol concentration, and his driver’s license was revoked in a civil administrative proceeding. The state supreme courts upheld the legal frameworks in each case, reasoning that the tests (or refusal penalties) were permissible under implied-consent laws and the search-incident-to-arrest doctrine. The U.S. Supreme Court granted certiorari to decide whether, and to what extent, the Fourth Amendment allows warrantless breath or blood tests incident to a lawful DUI arrest and whether states may criminalize refusal.
Whether the Fourth Amendment permits warrantless breath and blood tests as searches incident to lawful DUI arrests, and whether states may impose criminal penalties for refusing such tests.
Under the Fourth Amendment’s search-incident-to-arrest doctrine, warrantless breath tests are permissible following a lawful DUI arrest because they are minimally intrusive and sufficiently serve the government’s evidentiary interests. Warrantless blood tests, by contrast, are not permissible under that exception due to their significantly greater intrusion on bodily integrity and privacy and the availability of less intrusive alternatives. Accordingly, states may criminalize refusal to submit to a breath test incident to arrest but may not criminalize refusal to submit to a blood test. Implied-consent laws may impose civil penalties and evidentiary consequences for refusal, but they cannot deem consent to a blood test as a blanket substitute for the warrant requirement or authorize criminal penalties for refusing a blood draw.
The Court held that (1) warrantless breath tests are valid searches incident to lawful DUI arrests; (2) warrantless blood tests are not justified by the search-incident exception and generally require a warrant; (3) states may criminalize refusal to take a breath test but may not criminalize refusal to undergo a blood test. Applying these principles, the Court reversed Birchfield’s conviction for refusing a blood test, affirmed Bernard’s conviction for refusing a breath test, and vacated and remanded Beylund’s case for consideration of whether his consent to a blood test was voluntary given the erroneous advisory.
The Court employed the familiar balancing approach used to evaluate categorical applications of the search-incident-to-arrest exception, weighing the degree of intrusion on individual privacy against the government’s legitimate interests. Breath testing imposes only a modest physical intrusion (requiring a deep breath into a device), is unlikely to reveal private medical or other information beyond blood-alcohol concentration, and leaves no sample retained by the government. It effectively serves the government’s compelling interests in deterring drunk driving and securing reliable evidence of intoxication. Given those factors, breath tests fit within the traditional rationale of searches incident to arrest. Blood tests, however, are materially different. They require piercing the skin, extracting bodily fluid, and creating a sample that can reveal a broad array of personal information beyond BAC, raising heightened concerns for bodily integrity and informational privacy. Because breath testing is typically available and sufficient to meet the government’s evidentiary needs, blood testing is not necessary to vindicate the interests underlying the search-incident exception. Further, the natural dissipation of alcohol in the bloodstream does not create a per se exigency; under Missouri v. McNeely, exigent circumstances must be assessed case by case. Thus, absent exigency or voluntary consent, officers should obtain a warrant for a blood draw. Turning to refusal statutes, the Court emphasized that implied-consent frameworks may condition driving privileges on submission to testing and may impose civil consequences for refusal. However, they cannot be leveraged to impose criminal penalties for refusing an unconstitutional demand (i.e., a warrantless blood draw) or to conclusively deem consent where threats of unlawful penalties render consent involuntary. Accordingly, criminal refusal statutes are valid as to breath tests but invalid as to blood tests.
Birchfield refines Fourth Amendment doctrine at the intersection of bodily intrusions and DUI enforcement. It affirms the constitutionality of warrantless breath testing incident to arrest while requiring warrants (or valid consent/exigency) for blood draws, thereby cabining the scope of the search-incident exception. The decision also narrows the reach of implied-consent laws: states may maintain administrative penalties for refusal but may not criminalize refusal of blood tests or manufacture consent through misstatements of the law. For law students, Birchfield illustrates the Court’s modern categorical balancing within search-incident jurisprudence, the enduring force of McNeely’s case-by-case exigency requirement, and the nuanced treatment of consent in the presence of coercive statutory schemes.
As a categorical matter, yes—if there is a lawful custodial arrest supported by probable cause for DUI, a breath test may be administered without a warrant under the search-incident-to-arrest exception. The decision does not authorize warrantless breath testing absent a lawful arrest (e.g., during a mere traffic stop without arrest), nor does it dispense with other constitutional requirements such as probable cause for the arrest.
No. Birchfield holds that the search-incident-to-arrest exception does not justify warrantless blood draws. However, a warrantless blood test may still be lawful if another exception applies—most commonly exigent circumstances (assessed case by case under Missouri v. McNeely) or voluntary consent. Otherwise, officers generally must obtain a warrant for a blood draw.
Yes, but with limits. States may impose criminal penalties for refusing a breath test incident to a lawful DUI arrest. They may not criminalize refusal to submit to a blood test because such a demand generally requires a warrant or valid consent. Civil penalties (e.g., license suspension) and evidentiary consequences for refusal remain permissible under implied-consent laws.
Consent obtained through a threat of an unlawful penalty is not automatically valid. Birchfield remanded Beylund’s case to determine whether his consent was voluntary given the erroneous advisory that refusal of a blood test is a crime. Courts will evaluate voluntariness under the totality of the circumstances, and statements misstating the law can render consent involuntary.
Schmerber permitted a warrantless blood draw in a specific situation involving exigent circumstances. McNeely rejected a per se rule that alcohol dissipation alone creates exigency, requiring a case-specific analysis. Birchfield complements these cases by holding that breath tests are valid incident to arrest, while blood tests generally require a warrant unless Schmerber-type exigency or valid consent exists.
Birchfield v. North Dakota draws a constitutionally significant distinction between breath and blood testing in DUI cases, legitimizing warrantless breath tests incident to arrest but preserving robust Fourth Amendment protection against warrantless blood draws. The ruling reflects a pragmatic balance: it respects the government’s urgent interest in deterring and prosecuting drunk driving while recognizing the heightened privacy and bodily integrity interests implicated by blood sampling.
For practitioners and students, the case is a touchstone in search-incident doctrine and a reminder to analyze bodily intrusions with attention to both invasiveness and available alternatives. It continues to shape policing practices, legislative drafting of implied-consent statutes, and the voluntariness inquiry in consent cases where advisories or statutory penalties risk coercion.