[JURIST] The Texas 13th Court of Appeals [official website] ruled [opinion, PDF] on Wednesday that Texas’s implied consent law [text], which allows officers to take blood samples of motorists to determine impairment, is unconstitutional. The court was asked to examine the law after David Villarreal was stopped by police as a DWI suspect in 2012 and refused officers’ requests for him to perform a field sobriety test, as well as their subsequent requests for him to provide a blood sample to determine his level of intoxication. He was later given a blood test against his will, which confirmed to police that he was intoxicated. Villarreal moved to suppress the results of his blood test, which would have revealed a blood-alcohol-content of 0.16, claiming that he did not consent to giving a sample of blood. The appeals court agreed that his blood test results were inadmissible under the Fourth Amendment [text] of the US Constitution, ruling the implied consent law is unconstitutional.

The court relied on the US Supreme Court [official website] decision Missouri v. McNeely [SCOTUSblog backgrounder] which held that the Fourth Amendment may require a warrant [JURIST report] for a blood test in a drunk-driving investigation.The divided court ultimately held that “in drunk-driving investigations, the natural dissipation of alcohol in the bloodstream does not constitute an exigency in every case sufficient to justify a blood test without a warrant.” Last year the Minnesota Supreme Court [official website] upheld [JURIST report] the state’s driving while intoxicated implied consent law, ruling it is constitutional under the fourth amendment. In light of recent fourth amendment cases, some legal commentators have argued [JURIST op-ed] that investigative techniques have eroded the rights encompassed in the fourth amendment.