Almost a century has passed since a Tennessee schoolteacher was found guilty of teaching evolution to his students. We’ve come a long way since that happened on July 21, 1925. Haven’t we?

No, not really.

The Christian fundamentalism that begat the state law that John Scopes violated has not gone away. It regularly resurfaces in American politics, including today, when efforts to ban or dilute the teaching of evolution and other scientific concepts are part and parcel of a nationwide book-banning campaign, augmented by an effort to whitewash the teaching of American history.

The trial in Dayton, Tenn., that supposedly placed evolution in the dock is seen as a touchstone of the recurrent battle between science and revelation. It is and it isn’t. But the battle is very real.

Let’s take a look.

The Scopes trial was one of the first, if not the very first, to be dubbed “the trial of the century.”

And why not? It pitted the fundamentalist William Jennings Bryan — three-time Democratic presidential candidate, former congressman and secretary of State, once labeled “the great commoner” for his faith in the judgment of ordinary people, but at 65 showing the effects of age — against Clarence Darrow, the most storied defense counsel of his time.

The case has retained its hold on the popular imagination chiefly thanks to “Inherit the Wind,” an inescapably dramatic reconstruction — actually a caricature — of the trial that premiered in 1955, when the play was written as a hooded critique of McCarthyism.

Most people probably know it from the 1960 film version, which starred Frederic March, Spencer Tracy and Gene Kelly as the characters meant to portray Bryan, Darrow and H.L. Mencken, the acerbic Baltimore newspaperman whose coverage of the trial is a genuine landmark of American journalism.

What all this means is that the actual case has become encrusted by myth over the ensuing decades.

One persistent myth is that the anti-evolution law and the trial arose from a focused groundswell of religious fanaticism in Tennessee. In fact, they could be said to have occurred — to repurpose a phrase usually employed to describe how Britain acquired her empire — in “a fit of absence of mind.”

The Legislature passed the measure idly as a meaningless gift to its drafter, John W. Butler, a lay preacher who hadn’t passed any other bill. (The bill “did not amount to a row of pins; let him have it,” a legislator commented, according to Ray Ginger’s definitive 1958 book about the case, “Six Days or Forever?”)

No one bothered to organize an opposition. There was no legislative debate. The lawmakers assumed that Gov. Austin Peay would simply veto the bill. The president of the University of Tennessee disdained it, but kept mum because he didn’t want the issue to complicate a plan for university funding then before the Legislature.

Peay signed the bill, asserting that it was an innocuous law that wouldn’t interfere with anything being taught in the state’s schools. The law “probably … will never be applied,” he said. Bryan, who approved of the law as a symbolic statement of religious principle, had advised legislators to leave out any penalty for violation, lest it be declared unconstitutional.

The lawmakers, however, made it a misdemeanor punishable by a fine for any teacher in the public schools “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 had descended from a lower order of animal.”

Scopes’ arrest and trial proceeded in similarly desultory manner. Scopes, a school football coach and science teacher filling in for an ailing biology teacher, assigned the students to read a textbook that included evolution. He wasn’t a local and didn’t intend to set down roots in Dayton, but his parents were socialists and agnostics, so when a local group sought to bring a test case, he agreed to be the defendant.

The play and movie of “Inherit the Wind” portray the townspeople as religious fanatics, except for a couple of courageous individuals. In fact, they were models of tolerance. Even Mencken, who came to Dayton expecting to find a squalid backwater, instead discovered “a country town full of charm and even beauty.”

Dayton’s civic boosters paid little attention to the profound issues ostensibly at play in the courthouse; they saw the trial as a sort of economic development project, a tool for attracting new residents and businesses to compete with the big city nearby, Chattanooga. They couldn’t have been happier when Bryan signed on as the chief prosecutor and a local group solicited Darrow for the defense.

“I knew that education was in danger from the source that has always hampered it — religious fanaticism,” Darrow wrote in his autobiography. “My only object was to focus the attention of the country on the programme of Mr. Bryan and the other fundamentalists in America.” He wasn’t blind to how the case was being presented in the press: “As a farce instead of a tragedy.” But he judged the press publicity to be priceless.

The press and and the local establishment had diametrically opposed visions of what the trial was about. The former saw it as a fight to protect from rubes the theory of evolution, specifically that humans descended from lower orders of primate, hence the enduring nickname of the “monkey trial.” For the judge and jury, it was about a defendant’s violation of a law written in plain English.

The trial’s elevated position in American culture derives from two sources: Mencken’s coverage for the Baltimore Sun, and “Inherit the Wind.” Notwithstanding his praise for Dayton’s “charm,” Mencken scorned its residents as “yokels,” “morons” and “ignoramuses,” trapped by their “simian imbecility” into swallowing Bryan’s “theologic bilge.”

The play and movie turned a couple of courtroom exchanges into moments of high drama, notably Darrow’s calling Bryan to the witness stand to testify to the truth of the Bible, and Bryan’s humiliation at his hands.

In truth, that exchange was a late-innings sideshow of no significance to the case. Scopes was plainly guilty of violating the law and his conviction preordained. But it was overturned on a technicality (the judge had fined him $100, more than was authorized by state law), leaving nothing for the pro-evolution camp to bring to an appellate court. The whole thing fizzled away.

The idea that despite Scopes’ conviction, the trial was a defeat for fundamentalism, lived on. Scopes was one of its adherents. “I believe that the Dayton trial marked the beginning of the decline of fundamentalism,” he said in a 1965 interview. “I feel that restrictive legislation on academic freedom is forever a thing of the past, … that the Dayton trial had some part in bringing to birth this new era.”

That was untrue then, or now. When the late biologist and science historian Stephen Jay Gould quoted that interview in a 1981 essay, fundamentalist politics were again on the rise. Gould observed that Jerry Falwell had taken up the mountebank’s mission of William Jennings Bryan.

It was harder then to exclude evolution from the class curriculum entirely, Gould wrote, but its enemies had turned to demanding “‘equal time’ for evolution and for old-time religion masquerading under the self-contradictory title of ‘scientific creationism.’”

For the evangelical right, Gould noted, “creationism is a mere stalking horse … in a political program that would ban abortion, erase the political and social gains of women … and reinstitute all the jingoism and distrust of learning that prepares a nation for demagoguery.”

And here we are again. Measures banning the teaching of evolution outright have not lately been passed or introduced at the state level. But those that advocate teaching the “strengths and weaknesses” of scientific hypotheses are common — language that seems innocuous, but that educators know opens the door to undermining pupils’ understanding of science.

In some red states, legislators have tried to bootstrap regulations aimed at narrowing scientific teaching onto laws suppressing discussions of race and gender in the classrooms and stripping books touching those topics from school libraries and public libraries.

The most ringing rejection of creationism as a public school topic was sounded in 2005 by a federal judge in Pennsylvania, who ruled that “intelligent design” — creationism by another name — “cannot uncouple itself from its creationist, and thus religious, antecedents” and therefore is unconstitutional as a topic in public schools. Yet only last year, a bill to allow “intelligent design” to be taught in the state’s public schools was overwhelmingly passed by the state Senate. (It died in a House committee.)

Oklahoma’s reactionary state superintendent of education, Ryan Walters, recently mandated that the Bible should be taught in all K-12 schools, and that a physical copy be present in every classroom, along with the Ten Commandments, the Declaration of Independence and the Constitution. “These documents are mandatory for the holistic education of students in Oklahoma,” he ordered.

It’s clear that these sorts of policies are broadly unpopular across much of the nation: In last year’s state and local elections, ibook-banners and other candidates preaching a distorted vision of “parents’ rights” to undermine educational standards were soundly defeated.

That doesn’t seem to matter to the culture warriors who have expanded their attacks on race and gender teaching to science itself. They’re playing a long game. They conceal their intentions with vague language in laws that force teachers to question whether something they say in class will bring prosecutors to the schoolhouse door.

Gould detected the subtext of these campaigns. So did Mencken, who had Bryan’s number. Crushed by his losses in three presidential campaigns in 1896, 1900 and 1908, Mencken wrote, Bryan had launched a new campaign of cheap religiosity.

“This old buzzard,” Mencken wrote, “having failed to raise the mob against its rulers, now prepares to raise it against its teachers.” Bryan understood instinctively that the way to turn American society from a democracy to a theocracy was to start by destroying its schools. His heirs, right up to the present day, know it too.