Mitchell v. Wisconsin, 139 S. Ct. 2525

Background

Officer found Gerald Mitchell appearing intoxicated after driving; a preliminary breath test read ~0.24% BAC and Mitchell was arrested.
At the station Mitchell became too lethargic for an evidentiary breath test; officers transported him to a hospital where he lost consciousness.
While unconscious, hospital staff drew blood after an officer read Wisconsin’s implied-consent notice; analysis showed BAC ~0.222% and Mitchell was charged with OWI offenses.
Mitchell moved to suppress the blood-test results as an unreasonable, warrantless Fourth Amendment search; the trial court denied suppression and he was convicted.
Wisconsin relied on its implied-consent statute (which presumes unconscious motorists have not withdrawn consent); the state courts upheld the blood draw; the U.S. Supreme Court granted certiorari.
The Court vacated and remanded, holding that when a driver is unconscious and a breath test is not feasible, exigent circumstances generally permit a warrantless blood draw, but remand allows the defendant to attempt to rebut that general rule on the facts.

Issues

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Wisconsin’s implied-consent statute alone authorizes a warrantless blood draw from an unconscious motorist	Mitchell: statutory "deemed consent" cannot supplant Fourth Amendment warrant protections	Wisconsin: implied consent (plus use of highways) makes draw consensual and constitutional	Court did not accept implied-consent as the operative Fourth Amendment justification; looked to exigent-circumstances instead
Whether a warrant is required for a blood draw of an unconscious suspected drunk driver	Mitchell: warrant required unless exigency shown; Wisconsin conceded no exigency in this case	Wisconsin: (below) relied primarily on implied consent; at Supreme Court urged that unconsciousness fits exigency rationale	Plurality: when unconsciousness prevents an evidentiary breath test, exigent circumstances "almost always" permit a warrantless blood draw; remanded for defendant to show a rare rebuttal
Scope of exigent-circumstances doctrine for BAC testing generally	Mitchell: exigency must be shown case-by-case; McNeely controls (no categorical rule)	State (and concurring Justice Thomas): natural dissipation of alcohol creates exigency once probable cause exists	Plurality: adopts a categorical rule for the limited class of unconscious-driver cases; Justice Thomas would adopt a broader per se rule; dissent would adhere to McNeely’s case-specific inquiry
Standard for defendant to rebut the general rule for unconscious drivers	Mitchell: facts here (and similar cases) may show time to obtain a warrant; courts should require proof officers lacked time or that blood was sought only for evidence	Wisconsin: asserted statute sufficed; did not argue exigency below	Court: defendant may on remand attempt to show this was an unusual case where police would not have drawn blood absent investigatory motive or could not reasonably have concluded a warrant application would interfere with pressing duties

Key Cases Cited

Schmerber v. California, 384 U.S. 757 (1966) (exigent circumstances upheld where accident and related duties made delay to secure a warrant impracticable)
Missouri v. McNeely, 569 U.S. 141 (2013) (natural dissipation of alcohol alone does not create a per se exigency; exigency is case-specific)
Birchfield v. North Dakota, 579 U.S. _ (2016) (breath tests may be administered incident to arrest; blood tests are more intrusive and generally require a warrant absent exigency)
Katz v. United States, 389 U.S. 347 (1967) (warrantless searches are presumptively unreasonable absent established exceptions)
Michigan v. Tyler, 436 U.S. 499 (1978) (exigent-circumstances test: compelling need and no time to secure a warrant)
Brigham City v. Stuart, 547 U.S. 398 (2006) (emergency-aid exigency permits warrantless entry/search)
United States v. Santana, 427 U.S. 38 (1976) (hot pursuit exigency may justify warrantless entry/search)