Washington, D.C. – The Supreme Court Ruled Wednesday that police must obtain a warrant before drawing blood from suspected drunk drivers, asserting the dissipation of alcohol in the bloodstream alone does not give police the right draw blood against a person’s will.

The case before the Supreme Court was involves a Missouri man who was arrested in 2010 for suspicion of driving while intoxicated. Tyler McNeely was pulled over for speeding and exhibited the signs of intoxication; slurred speech and blood shot eyes, according to Missouri State Highway Patrol Officer Mark Winder.

McNeely admitted he had been drinking at a bar and failed field sobriety tests, but he refused to take a breathalyzer.  Officer Winder took McNeely to a local hospital where he drew blood from the man without his consent in order to preserve evidence necessary in securing a conviction.

Officer Winder argued, “Obtaining a search warrant in the middle of the night in Cape Girardeau County involves a delay, on average, of approximately two hours.”  During which time, the alcohol level in a person’s blood could diminish significantly.

That blood test revealed that McNeely’s blood alcohol level was twice the legal limit, but during his criminal the results from the blood test were suppressed. The court determined that McNeely’s case did not meet the criteria necessary —endangerment of life or loss of evidence– for a warrantless blood tests, stating in an unsigned opinion that, “Warrantless intrusions of the body are not to be undertaken lightly.”

A New York Times report noted that in a 1966 case, Schmerber v. California, the Supreme Court Ruled police did not need a warrant when the suspected driver accidentally injured or killed another motorist.

The Missouri State Supreme Court upheld the lower court’s decision, but law enforcement officers asked for more latitude asserting that in the time it takes to get a warrant, evidence can be lost and justice would not be served. Mothers Against Drunk Driving also threw their support behind warrantless blood tests.

But the ACLU argued that warrantless blood searches were a violation of person’s constitutional rights and were unnecessary. Many states have laws which make refusing a blood test or breathalyzer during a stop a criminal act.

In the Supreme Court decision, all but one of the Justices agreed that preserving evidence was not enough cause to violate a person’s Fourth Amendment rights, which bars unreasonable searches and seizures. Four of the Justices dissented in part emphasizing that the court’s decision in this case could further confuse law enforcement’s responsibilities under the Fourth Amendment.

“We hold that in drunk-driving investigations, the natural dissipation of alcohol in the bloodstream does not constitute an exigency in every case sufficient to justify conducting a blood test without a warrant,” said Justice Sonia Sotomayor, according to CNN.

Justice Clarence Thomas was the only Justice that believed warrantless blood tests did not violate a person’s constitutional rights.

In his dissent, Thomas said, “Because the body’s natural metabolization of alcohol inevitably destroys evidence of the crime. It constitutes an exigent circumstance,” CNN reported.

Drunk drivers are involved in almost a third of all fatal accidents, so it is in everyone’s best interest to stop these drivers. Cases like this can be perplexing because we sometimes have to figure out if the safety of others trumps the rights of an individual.