Missouri v. McNeely (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 U.S. Supreme Court ruled that police must generally obtain a warrant before subjecting a drunken-driving suspect to a blood test. The United States Supreme Court granted a petition for writ of certiorari on September 25, 2012. A divided 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. However, the Court left open the possibility that the “exigent circumstances” exception to that general requirement might apply in some drunk-driving cases.

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