Tag: DNA profiling

A Cheeky Decision from SCOTUS


The U.S. Supreme Court ruled today that police don’t need a search warrant before they open your mouth and take a swab of DNA.

The Supreme Court ruled in a 5-4 decision that DNA swabs are a “legitimate police booking procedure” that is allowed under the Constitution just like fingerprinting and mugshots.
The court’s swing voter Justice Anthony Kennedy wrote the majority opinion, which said DNA identification has become an important tool to help police identify suspects.

Supposed fascist Scalia actually sided with the liberal court on this one, pointing out — correctly in my view — that the state’s argument that they are using DNA primarily to identify people (and only investigating past crimes by coincidence) is absurd.

The Fourth Amendment forbids searching a person for evidence of a crime when there is no basis for believing the person is guilty of the crime or is in possession of incriminating evidence. That prohibition is categorical and without exception; it lies at the very heart of the Fourth Amendment. Whenever this Court has allowed a suspicionless search, it has insisted upon a justifying motive apart from the investigation of crime.

It is obvious that no such noninvestigative motive exists in this case. The Court’s assertion that DNA is being taken, not to solve crimes, but to identify those in the State’s custody, taxes the credulity of the credulous. And the Court’s comparison of Maryland’s DNA searches to other techniques, such as fingerprinting, can seem apt only to those who know no more than today’s opinion has chosen to tell them about how those DNA searches actually work

Of course, any DNA taken is going to be used to solve crimes. That’s precisely what they did in the case of Alonzo King, who was convicted of a six-year-past rape because of a DNA match drawn when he was brought in for an unrelated crime. While I’m a bit mixed on whether DNA swabs should be allowed, the Court’s reasoning, which compares fingerprinting to jabbing a swab in someone’s mouth and running it against a crime database, seems as odd to me as it does to Scalia.

(You should also read this article about the statistical problems in blind DNA database searches. If your are matching the DNA of someone you already suspect of a crime, those one in a million stats mean something. However, the DNA databases are so massive that, for a blind search, the chance of finding a bogus match for someone’s DNA on any crime is much much higher. If you have 300,000 crimes in your database, the chance of a one in a million match to something is actually one in three.)

I’ll post more commentary as it comes in.