A Junk Decision on Warrantless DNA Collection

You lost some important Fourth Amendment protection when the Supreme Court ruled yesterday in Maryland v. King that the police can take a DNA sample from an arrestee without a search warrant for purposes of general law enforcement rummaging.

The court was reviewing the constitutionality of Maryland's practice of collecting DNA from all arrestees -- without a search warrant or any individualized suspicion that the DNA will lead to evidence of a crime. Maryland is not alone in this practice; 28 states and the federal government all do the same thing. Once law enforcement has a DNA sample, it's sent to a lab to extract a portion of the sample, called a DNA profile. The lab then sends that profile to an FBI-maintained database called CODIS to be compared against other profiles from genetic material left at crime scenes with the hope of solving a cold case. That's what happened to King, who was arrested for assault and, upon arrest, had his DNA collected. As the assault case worked its way through the criminal justice system, King's DNA profile ultimately linked him to an earlier, unsolved rape. King was charged and convicted of that crime and sentenced to life in prison.

There's no question that collecting DNA is a "search" under the Fourth Amendment and so ultimately the case boiled down to the purpose for which the DNA was being collected. In the past, the Court has never allowed suspicionless searches for mere investigative, crime-solving purposes because this is the key problem the Fourth Amendment was written to protect against. The Court has only allowed suspicionless searches in limited "special needs" cases where the search is for a purpose other than crime investigation, such as at a border or a sobriety checkpoint. Over the the last two years, we've argued to courts throughout the country—including filing an amicus brief with the Supreme Court in King—that warrantless DNA collection from arrestees is unconstitutional because collecting, analyzing and searching their DNA only serves a law enforcement investigative purpose to solve cold cases, and thus doesn't fall under any of the "special needs" exceptions.

Unfortunately Justice Kennedy's majority opinion didn't see it that way. In finding DNA collection from arrestees to be constitutional, the Court relied on two faulty premises.

The Court found the "search" at issue was limited to the cheek swab to obtain the DNA rather than the searches that come after, namely running the DNA sample through the CODIS database. Just like its decision last year in United States v. Jones assessing the constitutionality of installing a GPS device by looking to the law of trespass, the majority once again refused to address the privacy issues involved in searching aggregated intangible data rather than physical places or things. This has implications for other kinds of searches that don't involve physical contact and are likely to reach courts in the future, including law enforcement use of facial recognition and drones flying around in public spaces.

Then the majority found the purpose of the search was identification—ensuring the police arrested the right person—and to determine the person's prior criminal history to help a court make a correct bail determination. In doing so, the majority found collecting DNA was no different than taking an arrestee's photograph or fingerprint. But this reasoning is wrong for two reasons.

First, DNA tells far more about a person than a mere picture or fingerprint. Instead, it provides police with a person's entire genetic makeup. And even when the DNA sample is reduced to the non-coding DNA profile entered into CODIS, that profile can tell who you're related to and who you're not.

Second, in Maryland, like all other jurisdictions that collect DNA from arrestees, there's no way DNA could be used to "identify" anyone (in the ordinary definition of "identify"—which means to indicate conclusively who that person is) or to affect a bail determination from the simple fact tha