In the aftermath of World War I, the Fundamentalist-Modernist Controversy brought a surge of opposition to the idea of evolution. By 1925, such legislation was being considered in 15 states, and passed in some states, such as Tennessee. The “American Civil Liberties Union” offered to defend anyone who wanted to bring a test case against one of these laws. John T. Scopes accepted, and he confessed to teaching his Tennessee class evolution in defiance of the Butler Act.
Scopes was convicted. However, the widespread publicity galvanized proponents of evolution. When the case was appealed to the Tennessee Supreme Court, the Court overturned the decision on a technicality (the judge had assessed the fine when the jury had been required to). Although it overturned the conviction, the Court decided that the law was not in violation of the First Amendment. The Court held, “We are not able to see how the prohibition of teaching the theory that man has descended from a lower order of animals gives preference to any religious establishment or mode of worship. So far as we know, there is no religious establishment or organized body that has in its creed or confession of faith any article denying or affirming such a theory.” Scopes v. State 289 S.W. 363, 367 (Tenn. 1927).
The interpretation of the Establishment clause up to that time was that Congress could not establish a particular religion as the State religion. Consequently, the Court held that the ban on the teaching of evolution did not violate the Establishment clause, because it did not establish one religion as the “State religion.” As a result the teaching of evolution remained illegal in Tennessee, and continued campaigning succeeded in removing evolution from school textbooks throughout the United States.