Edwards v. Aguillard was a 1987 United States Supreme Court case that said that creationism was not science. The Supreme Court said that it was religion, and could not be taught in American schools, because the United States Constitution (the set of rules that all American government must follow) does not allow the government to support one religion more than other religions, and so schools run by the government cannot teach religion as being true. This rule is known as the Establishment Clause.