Amid the spectacle of the Scopes trial in 1925 it was easy to forget that there were actual legal issues involved in the case. The defendant, a young teacher, John Thomas Scopes, was on trial for violating the Butler Act, a recently enacted law that forbade the state’s educators “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.” Scopes was recruited to be the defendant in a case intended to test the constitutionality of the Butler Act.
Accordingly, on the second day of the trial, the defense team moved to quash the indictment against Scopes, citing fourteen distinct points of Tennessee and US constitutional law. Not all of these points were plausible. The second point, for instance, was that the Tennessee constitution of 1870 requires the legislature to “cherish literature and science;” the inference that the legislature is not allowed to control what is taught in the state’s public schools is hard to credit.
Among the remaining points, two themes emerge. First, the Butler Act violated Scopes’s freedoms, especially his academic freedom and his freedom of speech. Second, by privileging a particular understanding of the Bible as inconsistent with human evolution, the Butler Act violated the separation of church and state. (The defense team invoked not the Establishment Clause of the First Amendment to the US Constitution but its equivalent in the Tennessee constitution of 1870.)
These themes are in tension. Consider what would happen if a public school teacher sought to teach creationism as a scientifically credible rival to evolution. Would the teacher have a constitutional right to do so, as the first theme would suggest? Or would the teacher, acting on behalf of the government, be constitutionally prohibited from doing so, as the second theme would suggest? In the event, however, the tension was unaddressed during the Scopes trial.
Instead, John Raulston, the presiding judge, denied the defense team’s motion to quash the indictment altogether. Scopes was convicted, and although his conviction was overturned by the Tennessee Supreme Court in 1927 — on the grounds that the fine of $100 had been improperly set by the judge rather than by the jury — the Butler Act remained on the books until 1967, when it was repealed by the Tennessee legislature.
Forty years after the Scopes trial, a Little Rock, Arkansas, teacher named Susan Epperson was told by her school to teach from a textbook that had recently been revised to include evolution. The directive would have forced Epperson to violate a 1928 Arkansas statute similar to the Butler Act, which had been enacted by initiative in the wake of the Scopes trial. She sued the state, and the case wound its way to the Supreme Court in 1968.
Like Scopes’s legal team, Epperson’s legal team argued against the constitutionality of the statute on both freedom of speech grounds and establishment of religion grounds. By then, the doctrine of incorporation — according to which the Fourteenth Amendment requires certain protections in the Constitution’s Bill of Rights to apply to the states — had been accepted, so Epperson’s legal team, unlike Scopes’s legal team, was able to invoke the First Amendment.
In its unanimous decision in Epperson v. Arkansas (1968), written by Justice Abe Fortas, the Supreme Court held that the Arkansas ban on the teaching of evolution violated “the Fourteenth Amendment, which embraces the First Amendment’s prohibition of state laws respecting an establishment of religion” (Justice Hugo Black dissented with respect to the establishment claim). Thus the second theme triumphed.
Justice Fortas’s reasoning was then generalized in Lemon v. Kurtzman (1971), a case not involving evolution, in which the Supreme Court articulated a three-pronged test for whether a given government action violated the Establishment Clause: a law must have a secular purpose, a predominantly secular effect, and not foster “excessive entanglement” between religion and government. For the next fifty years, the federal judiciary used the Lemon test and its offshoots, such as the so-called endorsement test, to adjudicate cases involving the separation of church and state.
Among those cases were McLean v. Arkansas (1982), Edwards v. Aguillard (1987), and Kitzmiller v. Dover (2005), in which policies requiring the teaching of “creation science” and “intelligent design” in the public schools were found to be unconstitutional. Meanwhile, a handful of cases also established that public school teachers have no free speech or free exercise rights to teach creationism, or to refuse to teach evolution, in their classrooms.
But as the Supreme Court began to be dominated by conservative justices, starting around Kitzmiller v. Dover, it increasingly expressed discontent with the Lemon test. In the recent, Kennedy v. Bremerton decision (2022), the Supreme Court declared that it “long ago abandoned Lemon and its endorsement offshoot” in favor of interpreting the Establishment Clause by “reference to historical practices and understandings” — which is just as vague as it sounds.
Jurisprudence is in a state of volatility
Also of concern is the Supreme Court’s decision in Mahmoud v. Taylor (2025), which in effect suggested that any educational policy alleged to substantially interfere with “the religious development” of K-12 students might be held to be unconstitutional. The door is thus open for demands that students be excused from learning about evolution, and perhaps in consequence, as Justice Sotomayor warned in her dissent, decisions to remove the topic from classrooms altogether.
The consequences of these recent Supreme Court decisions on evolution education are not yet clear. But church/state jurisprudence, once more or less settled in its general principles, is now clearly in a state of volatility. At a Scopes trial centennial conference held in Chattanooga, Tennessee, on July 19, 2025, John E. Jones III — the now-retired judge who presided over Kitzmiller v. Dover twenty years ago — offered a recommendation to the audience: “Buckle in.”
Further reading
Alexander Gouzoules and Harold Gouzoules, The Hundred Years’ Trial: Law, Evolution, and the Long Shadow of Scopes v. Tennessee, Johns Hopkins University Press, 2025.
Edward J. Larson, Trial and Error: The American Controversy over Creation and Evolution, third edition, Oxford University Press, 2003.
Edward J. Larson, Creationism in the Classroom: Cases, Statutes, and Commentary, West Academic, 2012.
