ArticleslgStudy

science

Missouri v. McNeely

Missouri v. McNeely is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Missouri v. McNeely rather than just read about it. In short: Missouri v. McNeely, 569 U.S. 141 (2013), was a case decided by United States Supreme Court, on appeal from the Supreme Court of Missouri, regarding exceptions to the Fourth Amendment to the United States Constitution under exigent circumstances.

Missouri v. McNeely — main illustration
Missouri v. McNeely — illustration

Key takeaways

  • Missouri v. McNeely belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Missouri v. McNeely to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Missouri v. McNeely from memory before moving on to harder problems.

Reference excerpt

Missouri v. McNeely, 569 U.S. 141 (2013), was a case decided by United States Supreme Court, on appeal from the Supreme Court of Missouri, regarding exceptions to the Fourth Amendment to the United States Constitution under exigent circumstances. The United States Supreme Court ruled that police must generally obtain a warrant before subjecting a drunken-driving suspect to a blood test, and that the natural metabolism of blood alcohol does not establish a per se exigency that would justify a blood draw without consent.

Background

At approximately 2:08 a.m. on October 3, 2010, Tyler McNeely was stopped after a highway patrol officer observed him exceed the posted speed limit, and cross over the centerline. The officer reportedly noticed signs of intoxication from McNeely, including bloodshot eyes, slurred speech, and the smell of alcohol on his breath. McNeely failed field-sobriety tests administered by the officer. After refusing to blow into a handheld breathalyzer, and stating that he would refuse a breathalyzer at the police station, the officer drove McNeely directly to a medical center instead of the station. The officer did not seek a warrant to conduct the blood test, but asked McNeely for his consent. McNeely was warned by the officer that by refusing a chemical test, his license would be revoked for one year. McNeely continued to refuse, and at 2:35 a.m., the officer proceeded to instruct the lab technician to draw a specimen of blood from McNeely. The results of the blood test showed a BAC of 0.154 percent, which was above the state's legal limit of 0.08 percent. McNeely was charged with driving while intoxicated, and later moved to suppress the results of his blood test, as he argued that it was done unconstitutionally as an unreasonable search and seizure.

Procedural history A trial judge sided with McNeely, ruling in his favor by suppressing the results of the blood test. The judge emphasized that conducting a blood test without a warrant constituted a breach of the suspect's Fourth Amendment protection against unreasonable searches and seizures. Later, state prosecutors argued that justifying the administration of the test without a warrant was valid because blood alcohol would metabolize with time, and a delay in obtaining a warrant would amount to destruction of evidence, citing the exigent circumstances exception in the 1966 United States Supreme Court decision Schmerber v. California. On appeal, the state appeals court stated an intention to reverse, but transferred the case directly to the Missouri Supreme Court. The Missouri Supreme Court affirmed the trial court's decision that the officer had violated McNeely's Fourth Amendment rights. The United States Supreme Court granted a petition for writ of certiorari on 25 September 2012.

Opinion of the Court A 5-4 Supreme Court affirmed the Missouri Supreme Court, agreeing that an involuntary blood draw is a "search" as that term is used in the Fourth Amendment. As such, a warrant is generally required. In its majority opinion, the Court found that because McNeely's "case was unquestionably a routine DWI case" in which no factors other than the natural dissipation of blood-alcohol suggested that there was an emergency, the court held that the nonconsensual warrantless blood draw violated McNeely's Fourth Amendment right to be free from unreasonable searches of his person. However, the Court left open the possibility that the "exigent circumstances" exception to that general requirement might apply in some drunk-driving cases.

See also Breithaupt v. Abram (1957) U.S. Supreme Court case in which the Court ruled that involuntary blood samples, taken by a skilled technician to determine intoxication, do not violate substantive due process under the Fourteenth Amendment Birchfield v. North Dakota (2016) A warrantless breath test, on the other hand, is constitutional. Mitchell v. Wisconsin (2019) U.S. Supreme Court case in which the Court ruled that in the event a driver is unconscious and therefore can't be given a breath test as an alternative to testing blood, exigent circumstances allow for the drawing of blood without a warrant.

References

External links Text of Missouri v. McNeely, 569 U.S. 141 (2013) is available from: CourtListener Google Scholar Internet Archive (docket files) Justia Oyez (oral argument audio) Supreme Court (slip opinion) (archived)

Worked examples

Example 1 — a first encounter with Missouri v. McNeely

Start with the simplest possible case. Write down what Missouri v. McNeely claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Missouri v. McNeely before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Missouri v. McNeely ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Missouri v. McNeely

In research
Missouri v. McNeely appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Missouri v. McNeely in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Missouri v. McNeely is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2012 in Missouri, Alcohol law in the United States, Blood tests, so understanding it makes those chapters shorter.
In everyday life
Look for Missouri v. McNeely outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Missouri v. McNeely” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Missouri v. McNeely in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Missouri v. McNeely means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Missouri v. McNeely out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Missouri v. McNeely in simple terms?

Missouri v. McNeely, 569 U.S. 141 (2013), was a case decided by United States Supreme Court, on appeal from the Supreme Court of Missouri, regarding exceptions to the Fourth Amendment to the United States Constitution under exigent circumstances.

Why does Missouri v. McNeely matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Missouri v. McNeely?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Missouri v. McNeely.

Tags

  • 2012 in Missouri
  • Alcohol law in the United States
  • Blood tests
  • Missouri state case law
  • United States Fourth Amendment case law
  • United States Supreme Court cases
  • United States Supreme Court cases in 2012
  • United States Supreme Court cases of the Roberts Court

Keep exploring