The Supreme Court decided today that the Bush Administration lacked authority to set up military tribunals for the Guantanamo detainees, and that the tribunals also violated both applicable military law and the Geneva Conventions.See also Balkin's longer assessment.
Justice Stevens wrote the main opinion, joined by Justices Souter, Ginsburg, and Breyer, and joined in part by Justice Kennedy, who wrote separately. Chief Justice Roberts, who joined in the opinion of the D.C. Circuit below, recused himself. Justices Scalia, Thomas, and Alito each wrote dissenting opinions.
As Marty notes over on SCOTUSBlog, the big news is that the Court has now held that Common Article 3 of the Geneva Conventions are judicially enforceable and binding on the President. That provision of the Geneva Conventions also bans cruel treatment and torture. The Supreme Court has decided that the Geneva Conventions aren't so quaint after all.
And Greenwald's take as well.
And here for the Scotusblog discussion.