In the 1920s, the popular politician, William Jennings Bryan, began a campaign to bring an end to the teaching of evolution in schools. Bryan argued in 1922: " Now that the legislatures of the various states are in session, I beg to call attention of the legislators to a much needed reform, viz., the elimination of the teaching of atheism and agnosticism from schools, colleges and universities supported by taxation. Under the pretense of teaching science, instructors who draw their salaries from the public treasury are undermining the religious faith of students by substituting belief in Darwinism for belief in the Bible. Our Constitution very properly prohibits the teaching of religion at public expense. The Christian church is divided into many sects, Protestant and Catholic, and it is contrary to the spirit of our institutions, as well as to the written law, to use money raised by taxation for the propagation of sects. In many states they have gone so far as to eliminate the reading of the Bible, although its morals and literature have a value entirely distinct from the religious interpretations variously placed upon the Bible."
Tennessee governor Austin Peay, agreed with Bryan and in 1925 he passed what became known as the Butler Act. This prohibited public school teachers from denying the Biblical account of man's origin. The law also prevented the teaching of the evolution of man from what it referred to as lower orders of animals in place of the Biblical account.
The American Civil Liberties Union (ACLU) announced that it would finance a test case challenging the constitutionality of this measure. John Thomas Scopes, a teacher at Rhea County High School in Dayton, Tennessee, was approached by engineer and geologist George Rappleyea, and asked if he would be willing to teach evolution at the Rhea County High School. Scopes agreed and was arrested on 5th May, 1925. America's most famous criminal lawyer, Clarence Darrow, offered to defend Scopes without a fee. Leading the prosecution was Arthur Thomas Stewart, the District Attorney and he was joined by William Jennings Bryan, who was financed by the World Christian Fundamental Association.
The trial began in Dayton on 11th July, 1925. Over 100 journalists arrived in the town to report on the trial. The Chicago Tribune installed its own radio transmitter and it became the first trial in American history to be broadcast to the nation. Three schoolboys testified that they had been present when Scopes had taught evolution in their school. When the judge, John T. Raulston, refused to allow scientists to testify on the truth of evolution, Clarence Darrow called William Jennings Bryan to the witness stand. This became the highlight of the 11 day trial and many independent observers believed that Darrow successfully exposed the flaws in Bryan's arguments during the cross-examination.
In his closing speech Bryan pointed out: "Let us now separate the issues from the misrepresentations, intentional or unintentional, that have obscured both the letter and the purpose of the law. This is not an interference with freedom of conscience. A teacher can think as he pleases and worship God as he likes, or refuse to worship God at all. He can believe in the Bible or discard it; he can accept Christ or reject Him. This law places no obligations or restraints upon him. And so with freedom of speech, he can, so long as he acts as an individual, say anything he likes on any subject. This law does not violate any rights guaranteed by any Constitution to any individual. It deals with the defendant, not as an individual, but as an employee, official or public servant, paid by the State, and therefore under instructions from the State.... It need hardly be added that this law did not have its origin in bigotry. It is not trying to force any form of religion on anybody. The majority is not trying to establish a religion or to teach it - it is trying to protect itself from the effort of an insolent minority to force irrellgion upon the children under the guise of teaching science."
Bryan went on to argue: "Evolution is not truth; it is merely a hypothesis - it is millions of guesses strung together. It had not been proven in the days of Darwin - he expressed astonishment that with two or three million species it had been impossible to trace any species to any other species - it had not been proven in the days of Huxley, and it has not been proven up to today. It is less than four years ago that Professor Bateson came all the way from London to Canada to tell the American scientists that every effort to trace one species to another had failed - every one. He said he still had faith in evolution but had doubts about the origin of species. But of what value is evolution if it cannot explain the origin of species? While many scientists accept evolution as if it were a fact, they all admit, when questioned, that no explanation has been found as to how one species developed into another."