[Article VI of the Constitution of the United States say that the constitution and the laws made under it shall be the supreme law of the land and the judges and the courts in every state shall be bound thereby.] 1
When we talk about the use of foreign law in decisions concerning U.S. constitutional cases we are talking about treaties to which the United States have signed to and/or affirmed.
In the landmark decision case [Roper v. Simmons] 2 the court held that [the execution of juvenile offenders violated several international treaties, including the United Nations Convention of