## Facts

- A Missouri patrol officer stopped Tyler G. McNeely around 2:08 a.m. for speeding and repeatedly crossing the centerline.
- The officer observed signs of intoxication, including bloodshot eyes, slurred speech, and the smell of alcohol; McNeely admitted drinking and performed poorly on field-sobriety tests.
- McNeely refused a portable breath test and was arrested for driving while intoxicated.
- At a hospital, after being advised of Missouri’s implied-consent law and consequences of refusal, McNeely again refused consent for a blood test.
- Without seeking a warrant, the officer directed a technician to draw McNeely’s blood around 2:35 a.m.
- The blood test indicated a blood alcohol concentration of about 0.154%.
- The trial court suppressed the blood-test result; the Missouri Supreme Court affirmed, finding no exigency beyond ordinary alcohol dissipation.

## Issues

1. Whether the natural metabolization of alcohol in the bloodstream creates a categorical exigency permitting warrantless, nonconsensual blood draws in all drunk-driving cases.
2. Whether exigent circumstances for a warrantless blood draw must be evaluated case by case under the totality of the circumstances.

## Decision

- The Supreme Court affirmed the suppression order.
- The Court held that alcohol dissipation does not create a per se exigency justifying warrantless, nonconsensual blood testing in every drunk-driving case.
- Exigency for a blood draw must be assessed case by case based on the totality of the circumstances.
- On these facts, the State did not show circumstances making it impractical to obtain a warrant before drawing blood.

## Legal Principles

- A compelled blood draw is a search involving a physical intrusion into the body and implicates strong privacy interests under the Fourth Amendment.
- Warrantless searches are presumptively unreasonable unless a recognized exception applies, including exigent circumstances.
- Exigent circumstances exist only when the needs of law enforcement make a warrantless search objectively reasonable, typically assessed under a totality-of-the-circumstances analysis.
- The risk of evidence loss from alcohol metabolization is a relevant consideration but, standing alone, does not automatically justify dispensing with a warrant.
- Modern warrant procedures (including remote applications) may reduce delay and must be considered when evaluating whether a warrant was reasonably obtainable.

## Conclusion

The Fourth Amendment generally requires police to obtain a warrant before conducting a nonconsensual blood draw in a drunk-driving investigation; the natural dissipation of alcohol is not, by itself, an exigency, and any claim of exigent circumstances must be justified by the specific facts of the encounter.


Missouri v. McNeely, 569 U.S. 141 (2013)