Prosecutors, judges and police in Wisconsin will have to make some adjustments after the recent Supreme Court ruling on warrantless blood draws in OWI cases. Wisconsin and 28 other states currently don't require a search warrant to draw blood from a person suspected of drunk driving. In effect, police have been able to forcibly administer a blood test without a driver's consent.
Wisconsin case law has established that law enforcement officials can force a drunk driving suspect to provide a blood sample without first obtaining a warrant in exigent circumstances. The reason behind this ruling has to do with the imminent destruction of evidence. As the body metabolizes alcohol, it removes it from the bloodstream, lowering a person's blood alcohol content.