All lawyers remember their first encounter with Erie v. Tompkins, a staple of the first year of law school. Erie still reverberates for substantive reasons as well. Via Volokh, we see that that the Supreme Court has handed down the latest on Erie questions in Shady Grove v Allstate (PDF), though the Court's fractured opinion (with interesting alliances) leaves things quite muddled :

JUSTICE SCALIA announced the judgment of the Court and delivered the opinion of the Court with respect to Parts I and II–A, an opinion with respect to Parts II–B and II–D, in which THE CHIEF JUSTICE, JUSTICE THOMAS, and JUSTICE SOTOMAYOR join, and an opinion with respect to Part II–C, in which THE CHIEF JUSTICE and JUSTICE THOMAS join. [. . .] JUSTICE STEVENS, concurring in part and concurring in the judgment. [. . .] JUSTICE GINSBURG, with whom JUSTICE KENNEDY, JUSTICE BREYER, and JUSTICE ALITO join, dissenting.

I'll try and provide a cogent analysis later today for the 2 readers interested. I happen to like these kinds of cases.