Aggregated News

WASHINGTON — About halfway through a Supreme Court argument on Tuesday over whether the police may take DNA samples from people they arrest, Justice Samuel A. Alito Jr. reflected on just how momentous the issue was.

 “I think this is perhaps the most important criminal procedure case that this court has heard in decades,” he said, adding: “This is what is at stake: Lots of murders, lots of rapes that can be solved using this new technology that involves a very minimal intrusion on personal privacy.”

“Why isn’t this the fingerprinting of the 21st century?” he asked.

But the value of such evidence to law enforcement was only one side of the equation, Justice Antonin Scalia said after hearing that Maryland had obtained 42 convictions based on DNA from people arrested there.

“Well, that’s really good,” Justice Scalia said. “I’ll bet you if you conducted a lot of unreasonable searches and seizures, you’d get more convictions, too. That proves absolutely nothing.”

Justice Ruth Bader Ginsburg seemed to agree that the practice may run afoul of the Fourth Amendment, which generally...