Fundamentalist Protestants felt their beliefs challenged in the 1920s. Secular culture of the time seemed to have little place for religion, and church attendance was in decline. A movement to defend traditional religion by emphasizing a literal interpretation of the Bible gained momentum in the 1920s and especially targeted Darwin's theory of evolution as a symbol for what was wrong in modern society. By the mid-1920s, a number of states had enacted laws prohibiting the teaching of evolution. The law was challenged in Tennessee by a young high school biology teacher named John Scopes.
Popularly known as the monkey trial, Scopes's trial was the first ever broadcast over radio and became a national event primarily because of the notoriety of the attorneys representing each side. The American Civil Liberties Union brought in Clarence Darrow, the most famous defense lawyer in the country, for Scopes, while the World Christian Fundamentalist Union engaged William Jennings Bryan, three-time presidential candidate and the former secretary of state, to assist the prosecution. The trial was a clash between these two men and the beliefs they represented. The high point came when Darrow called Bryan, a recognized lay authority on the Bible, as a witness, and Bryan admitted on the stand that it was possible that creation may not have taken place in six, 24-hour days, thereby refuting a literal interpretation of the Bible. Nonetheless, the jury found Scopes guilty of violating the state's anti-evolution statute, and the judge fined him $100.
The theory of evolution and its teaching was such a hot-button issue at the time that most everyone had a strong opinion on one side or the other. With so many opinions floating around, the defense had little trouble finding people to take the stand and didn't have to resort to calling animals to testify.
The verdict was later overturned in a higher court on a technicality.