In divided ruling handed down today, the U.S. Supreme Court held that Missouri police violated the 4th Amendment by obtaining a warrantless and nonconsensual blood sample from a man suspected of drunk driving. At issue in Missouri v. McNeely was the question of whether or not the rapid diminishment of alcohol in a suspect's bloodstream should entitle the police to enjoy a blanket emergency exception to the 4th Amendment when it comes to seeking blood tests in drunk-driving cases. Writing for a majority that also included Justices Antonin Scalia, Anthony Kennedy, Ruth Bader Ginsburg, and Elena Kagan, Justice Sonia Sotomayor held that the actions of the Missouri police violated the Constitution and, more significantly, rejected the government's sweeping argument in favor of a blanket 4th Amendment exception.

While "in some circumstances law enforcement officers may conduct a search without a warrant to prevent the imminent destruction of evidence," Sotomayor wrote, "it does not follow that we should depart from careful case-by-case assessment of exigency and adopt the categorical rule proposed by the State and its amici. In those drunk-driving investigations where police officers can reasonably obtain a warrant before a blood sample can be drawn without significantly undermining the efficacy of the search, the Fourth Amendment mandates that they do so."

In addition to Sotomayor's majority opinion, Chief Justice John Roberts filed an opinion concurring in part and dissenting in part, which was joined by Justices Stephen Breyer and Samuel Alito, and Justice Clarence Thomas filed a lone dissent.

Click below to watch me and Nick Gillespie discuss this case and several other notable cases from the current Supreme Court term.