My knee-jerk response is to agree with Scalia’s conclusion on the right of police to collect DNA at arrest:
The law authorized testing for purposes of identification, Justice Scalia wrote, but only for missing people and human remains. It said nothing about identifying arrestees. “Solving crimes is a noble objective,” he 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.”
Perhaps Scalia, Sotomayor, Ginsburg and Kagan are wrong, and the other Supremes are right. But spare me the illogic of saying that cops are doing it to identify the person in custody, which was the majority’s reasoning. Cops gather DNA in hopes they can tie the person under arrest to another crime.