The US Supreme Court ruled Monday that police may routinely force arrestees to provide a DNA sample that can later be used to solve other crimes without having to first obtain a search warrant.

In a 5-to-4 decision, the high court said that as long as authorities have probable cause supporting an initial arrest for a “serious” crime, the government may collect DNA from any arrestee, store it in a database, and use it to help solve other crimes.

Such a routine collection procedure is reasonable under the Fourth Amendment, the court said.

Writing for the majority, Justice Anthony Kennedy said a brief swab of a suspect’s cheek to collect the DNA sample was only a minor intrusion that would not offend an arrested suspect’s expectations of privacy.

In contrast, he said, the government has a significant interest in using DNA to positively identify the arrestee, including any violent history or propensity to flee during pre-trial custody.

“Upon these considerations the Court concludes that DNA identification of arrestees is a reasonable search that can be considered part of a routine booking procedure,” Justice Kennedy wrote.

The central issue in the case, Maryland v. King (12-207), wasn’t whether police could use DNA to ensure that the Alonzo Jay King arrested by Maryland police was the same Alonzo Jay King named in the arrest warrant.

Rather, the issue was whether police could use DNA obtained from someone arrested for one crime to link that same person to an entirely different crime without any independent showing of probable cause to believe the arrestee was involved in the second crime.

In a dissent, Justice Antonin Scalia took issue with Justice Kennedy’s focus on the use of DNA as a means of identification.

“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,” he wrote.

Justice Scalia’s reading of the Fourth Amendment includes special attention to the founding generation’s hatred of “general warrants” that had been used by the British to carry out open-ended, suspicionless searches.

The Fourth Amendment guarantees the “right of the people to be secure in their persons ... against unreasonable searches and seizures.” It requires a warrant upon a showing of probable cause.

Monday’s decision is significant because it establishes an important exception to that mandate.

The decision will make it easier for law enforcement officials to collect and store a larger volume of DNA samples – potentially to be checked against DNA recovered at crime scenes.

All 50 states require the collection of DNA samples from convicted felons. In contrast, 29 states and the federal government have laws allowing the collection of DNA samples from those who have merely been arrested for a crime, but not convicted.

“Today’s judgment will, to be sure, have the beneficial effect of solving more crimes; then again, so would the taking of DNA samples from anyone who flies on an airplane … applies for a driver’s license, or attends a public school,” Scalia wrote in his dissent.

“Perhaps the construction of such a genetic panopticon is wise,” he said. “But I doubt that the proud men who wrote the charter of our liberties would have been so eager to open their mouths for royal inspection.”

In a statement, the American Civil Liberties Union said the decision “creates a gaping new exception to the Fourth Amendment.”

Others saw it as a step forward. Officials at the Rape, Abuse and Incest National Network said the ruling reflects recognition at the high court of the importance of DNA to solving crimes.

Kennedy’s majority decision was joined by Chief Justice John Roberts, and Justices Clarence Thomas, Stephen Breyer, and Samuel Alito.

Joining Scalia’s dissent were Justices Ruth Bader Ginsburg, Sonia Sotomayor, and Elena Kagan.

DNA has become an essential law enforcement tool. It not only offers police a reliable means to positively identify an individual, it also provides a way to link an individual to an unsolved crime scene containing unidentified skin, blood, or other bodily fluids containing DNA.

Monday’s decision stems from the case of Alonzo Jay King, who was arrested in Wicomico County, Md. in April, 2009 for allegedly pointing a gun at several people.

Once in police custody, Mr. King was required to submit to a buccal swab of his cheek to provide a DNA sample for the state’s database. A Maryland law authorizes officials to take samples from anyone arrested in the state for a serious crime.

The sample was sent to a national database of DNA samples where it matched DNA collected at the scene of an unsolved rape six years earlier in Wicomico County.

King was charged with rape and robbery in the 2003 unsolved crime. He was later convicted of first degree rape and sentenced to life in prison.

His lawyer argued that Maryland violated King’s Fourth Amendment rights when officials took the sample of his DNA without first obtaining a warrant from a neutral judge.

The trial judge rejected the argument, but the Maryland Court of Appeals reversed. It ruled the police must first obtain a warrant before collecting DNA from an arrestee.

In reversing that decision, Kennedy compared the use of DNA to the routine use of fingerprinting during the booking process. Fingerprints can help identify a suspect and sometimes they also provide evidence linking a suspect to a crime or crime scene.

Kennedy suggested that fingerprinting has not been found to violate the Fourth Amendment because it was seen by judges as fitting within “the accepted means of processing an arrestee into custody.”

Scalia said that unlike DNA, fingerprinting is an effective means of identifying suspects. It works so well, he said, that there is no need for a separate, redundant DNA-based confirmation system.

“What DNA adds – what makes it a valuable weapon in the law enforcement arsenal – is the ability to solve unsolved crimes, by matching old crime-scene evidence against the profiles of people whose identities are already known,” he said.

“That is what was going on when King’s DNA was taken, and we should not disguise the fact. Solving unsolved crimes is a noble objective, but it occupies a lower place in the American pantheon of noble objectives than the protection of our people from suspicionless law-enforcement searches.”

Scalia added: “The Court disguises the vast (and scary) scope of its holding by promising a limitation it cannot deliver.”