Every minute costs you BAC, so the warrant can wait — right? Missouri v. McNeely closed that shortcut.
What did Missouri v. McNeely decide?
In drunk-driving investigations, the natural dissipation of alcohol in the bloodstream does not by itself create a per se exigency justifying a warrantless, nonconsensual blood draw. Exigency must be determined case by case, on the totality of the circumstances.
Missouri v. McNeely, 569 U.S. 141 (2013) — read the opinion on CourtListener.
What does McNeely allow?
- A warrantless draw where the totality genuinely shows exigency — for example, an accident with injuries that consumes the time a warrant would take
- Obtaining a warrant by telephonic or electronic means, which the Court pointed to as the reason the old shortcut is unnecessary
- A blood draw on valid consent, or under your state’s implied-consent framework where it applies
What does it NOT allow?
- A categorical rule that alcohol dissipation alone excuses the warrant requirement
- Skipping an available warrant because getting one is merely inconvenient
- Assuming implied-consent statutes authorize a forced draw — read Birchfield before you rely on that
How it plays out on the street
The practical answer is to make warrants fast rather than argue exigency after the fact. Know your county’s on-call judge procedure and whether electronic warrants are available, and note the time you started the process, because delay you can document is what builds a real exigency claim. When you do claim one, write the specific facts that ate the clock — a crash scene, injured parties, a hospital transport — not the chemistry of alcohol metabolism, which McNeely has already rejected.
Frequently asked questions
Do police need a warrant for a DUI blood draw?
Generally yes, absent consent or a genuine case-specific exigency. Alcohol dissipation alone doesn't create one.
When can blood be drawn without a warrant?
When the totality shows a real exigency — typically circumstances that consumed the time needed to get a warrant — or on valid consent.
Related cases
- Birchfield v. North Dakota (2016): Breath Test vs. Blood Test on a DUI Arrest
- Mitchell v. Wisconsin (2019): Can You Draw Blood From an Unconscious DWI Driver?
- NJ DWI Laws: A Patrol Officer’s Complete Field Reference
Carry the rule, not the guesswork. Every case in StreetSense is broken down like this — bottom line, limits, and the exact citation — verified against the real opinion and available fully offline on shift. Start the free trial.
StreetSense is an educational reference for law enforcement, not legal advice. Federal cases set the floor — your state constitution, statutes, and department policy can impose stricter limits. Always follow your state’s rule and your agency’s policy.
Spot an error? Email nick@mnsindustriesllc.com with the post and your source. Corrections to the app go out over the air. How we verify.