Evanescence of Blood Alcohol Does Not Eviscerate Warrant Requirement

Evidence of a DUI suspect’s intoxication may be disappearing by the minute, but that does not, by itself, give the police authority to conduct an involuntary blood draw without a warrant. The Supreme Court confirmed today, in Missouri v. McNeely, that to rely on the exigent circumstances exception to the warrant requirement, the officer must have probable cause, and there must be specific facts demonstrating exigent circumstances. The evanescence of blood alcohol is not enough by itself.

The Court refused to go along with Missouri’s request that all DUI blood draws be categorically justified by exigent circumstances (and therefore excepted from the warrant requirement) since BAC’s tend to drop with time after the incident. To start with, the Court noted the strong privacy interest in not having your body pierced by needles. The Court added that small delays are not fatal to the prosecution in DUI cases: that BAC evidence can not be destroyed by the suspect, and that the evidence dissipated “gradually and relatively predictably.” Contrast a DUI with a now-or-never situation, say, where a suspect might flush cocaine down the toilet if the police did not break down a door. The Court also noted that there were streamlined processes to obtain warrants in many jurisdictions, and that those could be pursued while escorting the suspect to the hospital, where most blood draws are performed. All this, and more, led the Court to conclude there should be no categorical rule that DUI investigations present exigent circumstances—any warrantless, involuntary blood draw must be justified on the specific facts of the case, if it is to be justified at all.

What does this mean? First, it is a victory for civil liberties and the vitality of the Fourth Amendment. Like an intrusion to one’s home, a forcible intrusion into your body to collect evidence against you is a profound invasion of privacy. Though the warrant requirement (or, alternatively, McNeely’s case-specific exigent circumstances requirement) will not stop involuntary blood draws, it adds a meaningful buffer between the individual and state. Detached and neutral magistrates may not be as big a buffer as a jury or grand jury, but they help prevent the most egregious abuses of individual liberties.

Second, notwithstanding the Court’s reassurances, it will make prosecution of some DUI cases harder. In Colorado, the law provides for involuntary blood draws in alcohol-related vehicular assault and vehicular homicide cases but not routine DUI investigations. But for those vehicular assault and vehicular homicide cases where there are not clear exigent circumstances, the police will now pursue warrants. In some of those cases, the pursuit of warrants will lead to delays. And no matter what the Supreme Court says, it is much harder to prove a DUI (or alcohol-based vehicular assault or vehicular homicide) with a blood test 3 hours after driving, as opposed to 1 ½ hours after driving. Yes, forensic toxicologists can perform retrograde extrapolation, but it is not an exact science and the longer the delay in testing, the greater the possible error in extrapolation.

Further, by reaffirming the state’s burden to show individualized exigent circumstances in each involuntary, warrantless blood draw, it creates opportunities for DUI lawyers to litigate. The state of Missouri (and concurring Chief Justice Kennedy) wanted a bright line rule to provide officers guidance on when they do and do not need warrants. Without the bright line rule, officers are more likely to make mistakes that result in suppression of evidence at a motions hearing. Criminal lawyers will enjoy their reaffirmed relevance.

In many ways, this is not a new rule of law, but in practice it should increase the burden on the state to show exigent circumstances in DUI investigations. The police, DA, and judge may not stop the exigent circumstances inquiry at “was his BAC likely falling?” To be sure, there is a cost to this liberty: the work of the police and prosecution will be harder. But the benefit is clear, too. An officer can not bypass the warrant requirement of the Fourth Amendment– strapping you down and having a nurse poke you with a needle– simply by invoking three letters: DUI.