In the case of Missouri v. Tyler McNeely, Mr. McNeely was arrested for DUI and then forced to give blood at a nearby hospital. His case went all the way to the United States Supreme Court where he successfully argued that forcing him to give blood without first getting a warrant violated his right to be free from an unreasonable search and seizure that is guaranteed by the Fourth Amendment to the U.S. Constitution.
The facts of McNeely's case are as follows:
While on road patrol at approximately 2 a.m., a Missouri police officer stopped McNeely's truck after noticing it speeding and repeatedly crossing the center line. The officer observed several signs that McNeely was intoxicated including McNeely's bloodshot eyes, his slurred speech, and the smell of alcohol on his breath. McNeely told the officer that he had drunk a couple of beers at a bar, and he appeared unsteady on his feet when he got out of his truck. After McNeely performed poorly on some roadside tests and refused to blow into a portable breath-testing machine, he was arrested for DUI.
The officer began driving McNeely to the police department, but when McNeely told him that he would refuse to blow into another breath-testing machine after arriving there, the officer instead took McNeely to a nearby hospital for blood testing without first getting a warrant. When they arrived at the hospital, the officer asked McNeely whether he would agree to a blood test. The officer told McNeely that if he refused to do so, his driver's license would be revoked for one year, and his refusal could be used against him in court. McNeely nevertheless refused. The officer then ordered a hospital lab technician to take a blood sample from McNeely. That sample was later used in court against McNeely.
The U.S. Supreme Court ruled in favor of McNeely saying:
1. When an officer in a typical DUI investigation can reasonably obtain a warrant before forcing someone to give blood, then he must do so.
2. Even though someone driving a car has less of an expectation of privacy than she does when inside her home, that driver still has a privacy interest in preventing a police officer from ordering her skin to be pierced with a needle.
3. Although blood drawn in a hospital by a lab technician is less intrusive than some other invasions of one's body, any forced intrusion into a human body implicates important, constitutionally-protected privacy interests.
4. A police officer's general interest in preventing drunk driving does not just justify her failing to get a warrant without first pointing to emergency circumstances that made it impractical for her to get a warrant in the first place.