DNA samples and the Fourth Amendment
Today the Court handed down Maryland v. King, finding that taking of DNA samples from arrestees is not a Fourth Amendment issue because it's used for identification, like photographs or fingerprints taken after arrest. I find Scalia's dissent more convincing -- he points out that the statute requires that the DNA be taken only after the arraignment, and that its processing takes months, so it's hardly comparable to fingerprints and photographs in terms of establishing who the defendant is. The dissent has an unusual group of signers -- Scalia is joined by most of the liberal wing, Justices Ginsburg, Sotomayor and Kagan.
The last footnote is amusing: "Compare, New York v. Belton, 453 U. S. 454 (1981) (suspicionless search of a car permitted upon arrest of the driver), with Arizona v. Gant, 556 U. S. 332 (2009) (on second thought, no)."