“Make no mistake about it: because of today’s decision, your D.N.A. can be taken and entered into a national database if you are ever arrested, rightly or wrongly, and for whatever reason. http://www.nytimes.com/2013/06/04/us/supreme-court-says-police-can-take-dna-samples.html?ref=us The point of D.N.A. testing as it is actually practiced, he said, is to solve cold cases, not to identify the suspect in custody. The Fourth Amendment forbids searches without reasonable suspicion to gather evidence about an unrelated crime, Justice Antonin Scalia said, a point the majority did not dispute.
“Solving crimes is a noble objective,” Justice Scalia concluded, “but it occupies a lower place in the American pantheon of noble objectives than the protection of our people from suspicionless law-enforcement searches. The Fourth Amendment must prevail.”

The law allowed testing for purposes of identification, Justice Scalia wrote, but only for missing people and human remains. It said nothing about identifying arrestees.

All 50 states require the collection of D.N.A. from people convicted of felonies. After Mr. King was convicted of assault, there would have been no Fourth Amendment violation had his D.N.A. been collected and tested, Justice Scalia wrote.
“So the ironic result of the court’s error is this: The only arrestees to whom the outcome here will ever make a difference are those who have been acquitted of the crimes of arrest.”

From the bench, Justice Scalia repeatedly invoked the generation that fought the Revolutionary War and framed the Constitution. “The proud men who wrote the charter of our liberties,” he said, “would not have been so eager to open their mouths for royal inspection.”