## Facts

- A witness reported to Wisconsin police that Gerald Mitchell was driving while intoxicated.
- Officers located Mitchell and observed signs of intoxication, including slurred speech and difficulty walking.
- A portable breath test indicated Mitchell’s blood-alcohol content (BAC) was about three times the legal limit.
- Police began transporting Mitchell to the police station for an evidence-grade breath test.
- During transport, Mitchell became so lethargic that officers could not administer the breath test.
- Officers diverted to a hospital for medical attention, and Mitchell lost consciousness on the way.
- At the hospital, an officer read the standard Wisconsin “Informing the Accused” statement used before chemical testing; Mitchell did not respond.
- Without a warrant, the officer directed hospital staff to draw Mitchell’s blood.
- The test showed Mitchell’s BAC remained almost three times the legal limit about 90 minutes after his arrest.
- Mitchell was charged and, over his objection, the trial court admitted the blood-test evidence; a jury convicted him.
- Mitchell appealed, arguing the warrantless blood draw violated the Fourth Amendment.
- The Wisconsin Supreme Court affirmed, relying on Wisconsin’s implied-consent law for unconscious drivers.
- The U.S. Supreme Court granted certiorari.

## Issues

1. Whether the Fourth Amendment permits a warrantless blood draw from an unconscious suspected drunk driver when police have probable cause and a breath test cannot be administered, based on the exigent-circumstances exception.
2. Whether a state’s implied-consent law for unconscious drivers can substitute for Fourth Amendment analysis, or whether courts must evaluate exigency under the totality of the circumstances.

## Decision

- The Supreme Court vacated the Wisconsin Supreme Court’s judgment and remanded.
- A four-Justice plurality concluded that when police have probable cause to believe a person has driven drunk and the person is unconscious such that a breath test is not feasible, exigent circumstances will generally permit a warrantless blood test.
- The plurality treated this as a general rule rather than an automatic one: the defendant may show that, in the specific circumstances, police could reasonably have obtained a warrant without meaningfully affecting the search.
- The plurality declined to uphold the blood draw based solely on implied consent as an independent Fourth Amendment basis.
- Justice Thomas concurred in the judgment on broader reasoning, concluding that the natural dissipation of alcohol in the bloodstream by itself creates exigency.
- Justice Sotomayor, joined by Justices Ginsburg and Kagan, dissented, arguing that unconsciousness does not eliminate the need for a case-specific exigency showing and that implied-consent laws cannot replace a warrant.
- Justice Gorsuch dissented separately, arguing the case should have been dismissed as improvidently granted.
- Remand was required because the Wisconsin Supreme Court had relied on implied consent rather than applying the exigent-circumstances framework described by the U.S. Supreme Court.

## Legal Principles

- A compelled blood draw to measure BAC is a search under the Fourth Amendment.
- Warrantless searches are presumptively unreasonable unless an established exception applies.
- Exigent circumstances may justify a warrantless blood draw when the needs of law enforcement make obtaining a warrant impracticable, including where delay risks loss of BAC evidence due to ongoing metabolization and where officers must address medical needs.
- When a DUI suspect is unconscious and a breath test cannot be given, exigency will usually be present because the situation often involves time pressure, medical transport, and practical limits on seeking a warrant.
- The “usually” qualifier matters: the defendant may attempt to show that a warrant was reasonably available in the particular case (for example, if officers had time and a workable warrant process).
- State implied-consent laws may bear on state criminal procedure, but they do not by themselves determine whether a search is reasonable under the Fourth Amendment.

## Conclusion

Mitchell v. Wisconsin held that, although a blood draw is a Fourth Amendment search, an unconscious suspected drunk driver’s situation will generally present exigent circumstances permitting a warrantless blood test when a breath test is not possible; because the Wisconsin Supreme Court upheld the search on implied-consent grounds rather than applying that exigency analysis to Mitchell’s facts, the U.S. Supreme Court vacated and remanded for further proceedings.


Mitchell v. Wisconsin, 139 S.Ct. 2525 (2019)