Government collection of DNA is as tantalizing to law enforcement as it is terrifying to those who see it as an unwarranted intrusion on privacy. A split Supreme Court on Monday took its stand on the side of law enforcement, finding that the government can take DNA from suspects arrested under suspicion of violent crime. The five-justice majority made the right call.

At issue was a Maryland law that requires people arrested for violent crime to give a DNA swab to authorities. In 2009, Maryland police took Alonzo Jay King Jr. into custody for assault; the DNA sample they collected matched DNA evidence from an unsolved rape investigation six years earlier. King went to prison for the rape, but he challenged the Maryland law under which the police took his DNA. After Maryland’s highest court threw out King’s conviction, it was up to the Supreme Court to decide if Maryland conducted a constitutional search when the state took King’s DNA — and in effect whether similar laws in states across the country are legal.

The majority found that the potential of DNA to serve as the 21st-century equivalent of fingerprinting justified laws such as Maryland’s. During booking, suspects have their prints taken as a matter of course. Police can then use that information to defeat aliases that suspects might be using, to obtain information on suspects’ criminal history and even to solve cold cases in which authorities recovered fingerprints that they couldn’t identify. Since DNA is an exceptionally precise way to identify people, handing over a swab should be seen as a similarly reasonable way to identify and process arrestees, part of building a picture of who they are and the dangers they pose.

This ruling will not create some sort of disturbing database in which every American’s risk of developing diabetes or cancer is just a click away from any curious cop. Several provisions in Maryland’s law make clear that it is to be used only to collect information that denotes identity and nothing else.

But a spirited dissent from Justice Antonin Scalia raised a different objection. Scalia argued that Maryland’s law isn’t really like fingerprinting because it is specifically geared toward solving cold cases, not identifying and processing arrestees. As in other avenues of criminal investigation, he argued, the Fourth Amendment requires that police have reason to think that a specific individual committed a specific crime before demanding DNA to prove it.

But, as the majority pointed out, the rapid advance of DNA identification technology promises to make it as efficient a tool in the administration of criminal justice as fingerprinting has been, serving a variety of legitimate ends at many stages in the system, including identification. The justices were right to allow that process to continue to play out.

The Washington Post (June 5)