Marbury v. Madison (1803)
“Under our Constitution, ‘[t]he judicial Power of the United States’ is ‘vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish.’ Art. III, § 1. That ‘judicial Power…extend[s] to…Treaties.’ Id., § 2. And, as Chief Justice Marshall famously explained, that judicial power includes the duty to ‘say what the law is.’ Marbury v. Madison (1803). If treaties are to be given effect as federal law under our legal system, determining their meaning as a matter of federal law ‘is emphatically the province and duty of the judicial department,’ headed by the ‘one supreme Court’ established by the Constitution.” C.J. Roberts, Sanchez-Llamas v. Oregon, 548 U.S. 331, 353–354 (2006).