Very interesting indeed! Especially this part:
Justice Stephen G. Breyer wrote in dissent that the court had misread the supremacy clause of the Constitution, which says properly ratified treaties "shall be the supreme law of the land" and that the treaties at issue did not need to be implemented by congressional legislation. "As a result, the nation may well break its word even though the president seeks to live up to that word and Congress has done nothing to suggest the contrary," Breyer wrote. He was joined by Justices Ruth Bader Ginsburg and David H. Souter.
Roberts said to accept Medellin's argument would make World Court decisions not only binding domestic law but also "unassailable."