WASHINGTON — A sharply divided Supreme Court today ruled that police can routinely take DNA from people they arrest, equating a DNA cheek swab to other common jailhouse procedures like fingerprinting.

“Taking and analyzing a cheek swab of the arrestee DNA is, like fingerprinting and photographing, a legitimate police booking procedure that is reasonable under the Fourth Amendment,” Justice Anthony Kennedy wrote for the court’s five-justice majority.

But the four dissenting justices said that the court was allowing a major change in police powers.

“Make no mistake about it: because of today’s decision, your DNA can be taken and entered into a national database if you are ever arrested, rightly or wrongly, and for whatever reason,” conservative Justice Antonin Scalia said in a sharp dissent which he read aloud in the courtroom.

Twenty-eight states and the federal government now take DNA swabs after arrests. But a Maryland court was one of the first to say that it was illegal for that state to take Alonzo King’s DNA without approval from a judge, saying King had “a sufficiently weighty and reasonable expectation of privacy against warrantless, suspicionless searches” under the Fourth Amendment.

But the high court’s decision reverses that ruling and reinstates King’s rape conviction, which came after police took his DNA during an unrelated arrest.

Kennedy wrote the decision, and was joined by Chief Justice John Roberts and Justices Samuel Alito, Clarence Thomas and Stephen Breyer.

Scalia was joined in his dissent by Justices Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan.