US Supreme Court building in Washington (Getty Images)
WASHINGTON -- A narrowly divided Supreme Court ruled Monday that police can collect DNA from people arrested but not convicted of serious crimes, a tool that more than half the states already use to help crack unsolved crimes.
The case, described by Justice Samuel Alito as "the most important criminal procedure case that this court has heard in decades," represented a classic test between modern crime-fighting technology and centuries-old privacy rights.
In the end, the justices had to balance the benefits and the intrusion of a simple cheek swab -- and the considerable benefits won out. Justice Anthony Kennedy wrote the majority's 5-4 decision, while Justice Antonin Scalia wrote the dissent.
Twenty-six states already collect DNA from those arrested for felonies or other serious crimes and upload it into a national database run by the federal government. The purpose: to find matches with unsolved crimes.
That's how Alonzo Jay King was connected to a Maryland rape case for which he ultimately was convicted. Arrested in 2009 on an assault charge, King was linked by DNA evidence to the 2003 rape.
The Maryland Court of Appeals threw out his conviction, ruling that police needed a warrant or at least reason to suspect him of another crime before swabbing his cheek. The state, backed by the federal government, brought the case to the Supreme Court.
The justices have been inundated in recent years with difficult Fourth Amendment cases as well as others involving modern technology. Last year, they held that police could not attach a GPS tracking device to a car in order to monitor a suspect's movements. This year, they ruled that using a drug-sniffing dog with reasonable suspicion was OK -- but not at the door of a private home. And they decided that executing a search warrant after a suspect had left his home was out of bounds.
Modern technology presents a problem, however, particularly for justices who try to adhere to the Constitution. The framers didn't have GPS or DNA to contend with in the late 18th century. In February, the court grappled with the patent rights of self-replicating soybeans. This month, they debated about a breast cancer detection technology that comes from human genes.
In this case, Maryland likened DNA to fingerprinting and other tools used to identify suspects. But opponents noted that police take DNA from people upon arrest to help in other investigations -- a process that can lead to false hits and wrongful convictions.
During oral argument in February, Justice Sonia Sotomayor worried that DNA swabs could find their way into the nation's schools and workplaces. Justice Elena Kagan quipped that if it works so well, "why don't we do this for anybody who comes in for a driver's license?"
On the other side were most of the court's more conservative justices, but the debate revealed an unlikely mix. Most convinced about the promise of DNA was Alito, who called it "the fingerprinting of the 21st century." He noted that the criminal justice system has "lots of murders, lots of rapes that can be solved."
The oral argument also revealed an unlikely split among the justices. While liberal Justice Stephen Breyer said the practice targets only those arrested for serious crimes -- and for a worthy cause -- Scalia said, "Sometimes the Fourth Amendment gets in the way."
The case received additional attention from the parents and family members of crime victims who have fought for years to expand DNA searches.
Jayann and Dave Sepich have led that effort through the organization DNA Saves. Their daughter Katie was brutally raped and strangled at the age of 22 a decade ago. By the time her killer was identified through DNA evidence, he had committed other crimes.
Last year, Congress passed the Katie Sepich Enhanced DNA Collection Act, which President Obama signed in January. It creates a grants program to help states pay for the expanded system.
"It's the right thing to do," Obama said of taking DNA from arrestees in a 2010 appearance on America's Most Wanted. "This is where the national registry becomes so important."
On the other side of the debate are civil liberties advocates who worry that DNA is subject to contamination, misinterpretation, sample switches and fraud.