John Scopes opposed the Butler Act because it criminalized teaching evolution in Tennessee’s public schools, a law he and others saw as an unconstitutional restriction on education and free inquiry. But the full story is more nuanced than a single teacher taking a principled stand. Scopes was recruited into the fight, and his opposition was as much a collaborative legal strategy as it was a personal conviction.
What the Butler Act Actually Banned
Signed into law in March 1925, the Butler Act made it a misdemeanor for any teacher in a Tennessee public school to “teach any theory that denies the story of the Divine Creation of man as taught in the Bible, and to teach instead that man has descended from a lower order of animals.” The penalty was a fine between $100 and $500 per offense, roughly $1,700 to $8,500 in today’s dollars. The law applied to every public university, normal school (teacher training college), and K-12 school receiving state funding.
The act didn’t ban all discussion of biology or even all references to evolution in a broad sense. It specifically targeted the teaching that humans descended from earlier animal species. That narrow focus made it both easier to violate and harder to defend, because the standard biology textbook already in use across Tennessee covered exactly that topic.
Why Scopes Got Involved
Scopes wasn’t a crusading activist looking for a fight. He was a 24-year-old general science teacher and football coach in Dayton, Tennessee. For two weeks he had filled in for an absent biology teacher, covering material from the state-adopted textbook, George William Hunter’s A Civic Biology. That textbook included a discussion of evolutionary theory, which meant that any teacher faithfully following the state curriculum was technically breaking state law.
The opportunity to challenge the Butler Act came from outside Dayton. The American Civil Liberties Union placed advertisements in Tennessee newspapers offering to cover the legal expenses of any teacher willing to serve as a test case against the law. Local business leaders in Dayton saw a chance to put their small town on the map and approached Scopes about volunteering. He agreed, later recalling that he wasn’t even certain he had explicitly taught evolution during his substitute teaching stint, though the textbook he assigned clearly contained the material.
This matters for understanding Scopes’s opposition. He didn’t wake up one morning outraged and march to the courthouse. He was presented with a situation where a law conflicted with the material teachers were expected to teach, and he was willing to be the person who tested whether that law could stand.
The Principles Behind His Stand
Scopes and his legal team, led by the famous trial lawyer Clarence Darrow, challenged the Butler Act on constitutional grounds. Their core arguments centered on a few key ideas.
First, the law forced teachers to choose between following the approved state curriculum and obeying state criminal law. Tennessee had adopted Hunter’s A Civic Biology as its official textbook, and that book discussed human evolution. A teacher couldn’t do the job without risking prosecution. That contradiction struck Scopes and the ACLU as fundamentally unfair.
Second, the defense argued the act violated principles of academic freedom. The state was dictating not just what could be taught, but what scientific ideas were permissible to discuss in a classroom. For Scopes and his supporters, banning a well-established scientific theory because it conflicted with a religious text crossed a line between church and state.
Third, there was a broader concern about the precedent. If Tennessee could outlaw the teaching of evolution, other states could ban any scientific concept that offended prevailing religious beliefs. The Butler Act wasn’t just about one theory in one state. It represented a model that anti-evolution activists were pushing across the country.
The Textbook at the Center
Hunter’s A Civic Biology played a surprisingly central role in the conflict. The book had been the standard biology text across most of Tennessee, adopted by the state itself. It discussed evolutionary theory as mainstream science, which it was. When the Butler Act passed, it instantly put every biology teacher using the state-approved curriculum in legal jeopardy.
Hunter himself seemed baffled by the controversy. He reportedly thought the entire dispute over teaching evolution was a misunderstanding. While the national media turned the upcoming trial into a spectacle, Hunter was on vacation in Glacier Park, largely unaware of the storm. He did make one small revision to the textbook around the time Scopes was indicted, adding a single sentence: “It must not be considered that man evolved from a monkey.” Later editions went further, replacing the word “evolution” throughout the book with “heredity and development,” a cautious rebranding that set a pattern other publishers would follow for decades.
What Happened at Trial
The trial took place in July 1925 in Dayton and became one of the most publicized court cases in American history, often called the “Scopes Monkey Trial.” Reporters flooded into town. The prosecution was led by William Jennings Bryan, a three-time presidential candidate and prominent Christian populist. The defense brought Darrow, arguably the most famous lawyer in the country.
The trial’s most dramatic moment came when Darrow called Bryan himself to the witness stand as an expert on the Bible, grilling him on whether scripture should be interpreted literally. Bryan struggled under questioning, and the exchange became a defining cultural moment in the debate between science and religious fundamentalism.
Scopes was found guilty and fined $100. That was the expected outcome. The entire point was to get a conviction that could be appealed to higher courts, where the constitutionality of the Butler Act could be tested. On appeal, the Tennessee Supreme Court overturned the conviction on a technicality: the judge had set the fine amount himself, when Tennessee law required any fine over $50 to be set by the jury. By tossing the conviction on procedural grounds rather than ruling on the law’s constitutionality, the court effectively prevented the case from reaching the U.S. Supreme Court.
The Butler Act’s Long Aftermath
The Butler Act remained on the books in Tennessee until 1967, more than 40 years after the Scopes trial. It was never again used to prosecute a teacher, but its chilling effect was real. Textbook publishers softened or removed evolutionary content to avoid controversy in southern markets. Teachers self-censored. The law achieved through intimidation what it rarely needed to enforce through prosecution.
Scopes himself never returned to teaching in Tennessee. He went on to study geology at the University of Chicago and spent his career in the oil industry. He remained a quiet figure, more symbol than activist. His willingness to lend his name to the case gave the ACLU the test defendant it needed, even if the legal strategy ultimately failed to strike down the law. The constitutional question he helped raise, whether states can ban the teaching of evolution, wasn’t definitively settled by the Supreme Court until 1968, in a case from Arkansas.