The Fourth Amendment, with its prohibition against unreasonable searches and seizures, provides one of the core protections of the Constitution, so it's not surprising that the Supreme Court was divided 5-4 last week in upholding the conviction of a man through DNA testing, a sensitive issue for those who prize civil liberties.
The surprise was the scrambling of the court's usual ideological coalitions. Justice Anthony M. Kennedy wrote the majority opinion. In filing a dissent, the arch-conservative Justice Antonin Scalia had the unlikely support of three liberal justices -- Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan.
There's no argument that a DNA sample taken from someone arrested by the police is a search of sorts, but the key word in the amendment is "unreasonable." On reasonableness grounds, the majority had the best of this argument. The decision to restore the conviction of a man arrested on a different charge but identified and subsequently tried as a rapist because of a DNA test was the right one.
In 2009, Alonzo King was arrested in Maryland and charged with first- and second-degree assault for menacing a group of people with a shotgun. As part of a routine procedure, a sample was taken from his mouth with a swab. That sample linked him to an unsolved 2003 crime, in which a man who had concealed his face broke into a woman's home and raped her. King was convicted of the rape, but the DNA test was later held to be unconstitutional by a Maryland appeals court.
In upholding the search's legality, the Supreme Court noted that the intrusion of the swab test was negligible and that the Maryland DNA Collection Act served a well-established, legitimate government interest. Moreover, it said that the only difference between DNA analysis and the traditional fingerprint databases is "the unparalleled accuracy DNA provides."
DNA, of course, can be a window into family histories and genetic dispositions, which might be alarming if the Maryland law did not specifically limit testing to identification. Only those charged with serious crimes are tested. Fourth Amendment purists might be reassured but Justice Scalia was not, basing his analysis as always on what the tyranny-fearing Founding Fathers might have thought.
The trouble with this is that DNA testing could not be dreamed of in their day -- indeed, fingerprinting was at least a century away from being used. Besides, the purist approach sells the Founding Fathers short. They were not against scientific progress and were resolutely practical men. If they had to choose between a hypothetical threat and a reasonably applied test that beyond doubt can convict the guilty and exonerate the innocent, they might have decided as the Supreme Court did.