Recently, after a particularly invigorating car wash, I had a yen for a slushie. Maybe the warming weather inspired me. Perhaps the proud signage of the QuikTrip convenience store nearby activated an unconscious desire. No matter, a slushie I did get. At QuikTrip, it’s called a Freezoni, a curious, quasi-Italian aspiration that bears no relation to the dispensed product. To my palate, the slushie wasn’t good: too wet, not frozen enough, like it was already half-melted from being left too long in a vehicle cup holder.

This made me wonder: Why are slushies so different from one another? Then the thought solidified into a more existential brain freeze, as I realized that I could not even guess what might separate a Freezoni from a Slurpee, let alone an Icee from a slush. What the hell is a slushie, anyway? I had no idea, and barely any intuition.

Now I am enlightened. If you’ve ever been enthralled by one slushie and disappointed by another, it’s probably because you may be keying into qualities of which you’re not aware: carbonation, expansion, density, flavor intensity. But Big Slushie doesn’t really care whether you understand these differences, because Big Slushie doesn’t care about your needs. It exists to help convenience stores, food chains, and event providers maximize profit margins for impulse purchases, while framing those purchases to you, the slurper, as nostalgic memories of childhood delight. This is a difficult truth, and you may regret your loss of innocence in its pursuit.

“We don’t really talk about them as slushies.” That’s the first thing I learned from Tyler Parker, marketing manager for the Icee Company. Sure, normal people like you and me might talk about them, broadly, in reference to a class of icy, flavored bevvies drunk easily through a straw. (If you’re eating flavored frozen water with a spoon, or licking it from a cup, that’s an “ice.” A snow cone is an ice.) But the slushie is not, in fact, a superordinate category, not if you’re in the frozen-beverage business anyway.

Parker’s company, whose bright blue-and-red logos you’ve surely seen at fairs, movie theaters, and Target cafés, makes something called a “frozen carbonated beverage,” or FCB. Its Icee, he would proudly say, is the OG FCB. In 1958, a Kansas Dairy Queen operator named Omar Knedlik accidentally invented FCBs when his soda fountain malfunctioned. He had to serve bottles from the freezer instead, which foamed out cola when cracked open. People loved them, so Knedlik strapped an automobile air conditioner to a dispenser and turned the botch into a business. He wanted to call the product Scoldasice (as in “’s cold as ice,” not “scold-a-size,” which sounds like a 1980s fitness gimmick), but a friend wisely suggested “Icee” instead. With partners, Knedlik perfected the machine and began to sell it. Among his customers was the convenience-store chain 7-Eleven, which developed its own brand name for the FCB product, Slurpee. That’s right, a Slurpee is the same product as an Icee, but sold under a private-label trademark. Same for a product you may have seen called “Arctic Blast”—just another Icee-Slurpee, a sibling in the family.

[Read: The ice diet]

The carbonation in Icees, Slurpees, and other FCBs provides an airy texture and a muted jolt, but also—when combined with yucca extract, a foaming agent—a surprisingly smooth texture and rich mouthfeel. Indeed, the fizz can be obscured so completely in the foam that you might not even have known that these drinks were carbonated. Bubbles also cause the dispensed product to expand, which is why your Slurpee or your Icee or your Arctic Blast inflates a bit after pouring, sometimes up and out of the domed lid to exasperate your parents.

Parker contrasts FCBs such as Icees with frozen uncarbonated beverages, or FUBs. Some of the frozen-beverage providers I spoke with articulate these names as initialisms (Eff You Bee), but Parker just says “fub,” as if to underscore its meager standing by means of phonics. When Parker does call a drink a slushie, he means to signal that it’s not the premium, carbonated kind of frozen drink, just a FUB. The Slush Puppie is a FUB; so is Dairy Queen’s Misty (formerly Mister Misty; kids these days got no respect), and the Sonic Drive-In fruity slush. A FUB can be good, of course, but it’s not really special. Anybody with some flavoring, some ice, and a blender can make a FUB. But an FCB, that requires its own equipment, supplies, and careful management.

To ensure the consistency of its branded FCBs, Parker’s team offers end-to-end service to its clients, including machines, flavor concentrates, maintenance of equipment, and marketing and sales support. But Icee’s grand designs on frozen-beverage domination span the slushiverse. In 2006, the company bought Slush Puppie, a classic FUB, then reformulated it with fruit juice and started selling the beverage in schools as “Juice 100.” When you order a frozen Coke at Burger King, that’s an Icee FCB. Same for those Mountain Dew slurp-alikes at Taco Bell. Big Slushie is real.

Or at least, that’s what the Icee Company would like me to believe. Isabel Atherton, the director of marketing at Sunny Sky Products, tells a different story. Her company makes concentrates for frozen drinks and sells them B2B. (Retailers choose which drink-making equipment to buy and how to service it.) Sunny Sky’s flavors are sometimes licensed from major food brands, such as Jarritos and Jolly Rancher, to allow for slushie lines with broad consumer recognition. Gas stations, for example, might try to sell you a Reese’s Freeze, thanks to Sunny Sky’s unholy interventions. Atherton says its flavors can be found at RaceTrac, Circle K, Wawa, QuikTrip, and many other convenience-store chains (“C-stores,” as insiders call them).

To maximize reach, Sunny Sky designs its products to work in either carbonated or uncarbonated machinery. “Most C-stores already have equipment,” Atherton told me. “What we try to do is to talk to manufacturers and test our products in their equipment.” In one machine, the crystals might be bigger, dulling the Jolly Rancher taste. Another one that produces smaller crystals might make the drink sweeter.

In other words, where Icee focuses on an end-to-end solution, Sunny Sky meets cost-conscious C-store operators where they are. A FUB machine is cheaper to buy and operate. An FCB machine is more expensive but self-contained, reducing operating complexity and increasing uptime. A drink’s “overrun”—the degree to which it expands in a carbonated-service machine—also has a direct impact on margins. More carbon dioxide means a fluffier beverage that uses less syrup and yields more profit. Icee and Slurpee may be powerful brand names, but Atherton dismisses their importance to frozen-beverage consumers. “‘Icee’ is like saying ‘Kleenex,’” she said. It’s a generic term—just another name for slushie.

She might have a point. I hadn’t even noticed QuikTrip’s Freezoni brand name until I started researching this story, even though it was emblazoned across the front of the machine that dispensed my drink. Ask a carload of unquenched souls, Do you want to get a Slurpee?, and they won’t necessarily assume you mean a stop at 7-Eleven. The buyer of a frozen drink won’t know the difference between an FCB and a FUB, and may have no expectations either way. “People don’t know the technical piece of it,” Parker admitted, and Atherton, along with every other frozen-beverage-industry insider I spoke with, agreed.

In place of knowledge about slushies, or even cogent preferences, all we have is our nostalgia. When I asked Parker to explain how his business works—what, exactly, does the Icee Company sell?—he kind of left orbit. “We exist to give people the best excuse to be a kid,” he said. “It’s a ‘kid in a cup’—an escape, an experience, something that’s going to give them a spark of joy.” I mean, it’s a slushie—err, FCB—but, you know, I get it. When I was a kid, my dad’s office sat across the street from a 7-Eleven. We’d walk over sometimes to get a Slurpee, and when I search my mind to justify why I even recall the memory, the essence of the product does glow at its center: light and expansive, full of possibility.

[Read: A definitive ranking of Dairy Queen Blizzard flavors]

In the same way, a Slurpee from a Speedway gas station (owned by 7-Eleven) or an Icee at an AMC theater serves as the bookmark for a particular sense memory. But the backroom machinations of the slushie space also undermine our recollections, sloshing them together in a vat of cherry-red confusion. A Slush Puppie or DQ Misty is looser and more liquid than an Icee or a Slurpee, for example. A Sonic slush is icier, which explains why it’s so easy to slurp out all the color from that drink and end up with a cup of crushed, unflavored ice. Even Taco Bell’s FCBs, which Parker represented to be “his” (as in, a product of the Icee Company), aren’t as fluffy as Burger King’s. QuikTrip’s Freezoni—which launched my journey to the land of slush—expands much less, making the resulting drink heavier and wetter. In Canada, yucca extract is not approved for food use, so the Slurpee that you buy in Winnipeg or Saskatoon will be thinner than the one you get in Texas or Wisconsin.

These matters are somewhat secretive within the industry. One machine salesman I spoke with speculated that C-stores carefully test and tune the properties of their machines, such as syrup concentration and overrun, to produce the best margins on the lowest cost in their particular markets: “In Tennessee, they like it really light and fluffy,” he told me. When I pressed a QuikTrip representative about the lack of foam in my Freezoni, she stopped responding to my inquiries. Similar questions spooked the equipment sales guy, too; he was scared of running afoul of his marketing department, and didn’t want to be cited by name.  At some convenience stores, he told me, the slushies are heavier and wetter by design. “They have determined their drink profile,” he said ominously, like a dark ice warlock.

Any consumer good can be mysterious. Who really knows what’s in a soda, or a hamburger, or a toothpaste? Branding covers over those questions, so arbitrary choice can masquerade as preference. But we tend to think it’s easy to distinguish between categories: A cola is not a sports drink; coffee isn’t tea. Slushies violate this expectation. Imagine going into a café and saying, “Give me a cup of the hot stuff,” and then accepting whatever they pour you as if it were the specific object of your desire. That’s what it is to buy a slushie.

Like Parker, Atherton described the purchase of a slushie as a feeling in itself, “like going out for ice cream.” According to John Pahic, who distributes the Taylor Company’s frozen-beverage machines for the Midwest Equipment Company, even regional “preferences,” such as the Tennessee foam, might have less to do with people’s palate than their life history—a slush ideology of sorts. You like what you know. And given the emotional, nostalgic nature of slushies, memory and habit rule.

When it comes to slushies, our brains are frozen. To us, they’re special treats that signify a special time—a hot summer day, a movie screening, a trip to the fair. Naturally the businesses that sell slushies see them differently, as high-margin impulse buys, tweaked to maximize the flow of capital. Your frozen drink is but a mere add-on to your entry ticket or taco-supreme order or tank of gas, and your (unconscious) frozen-beverage preferences have been exploited to produce compliant purchasing. The true customer of Big Slushie isn’t you, the slurper, but the C-stores who would tempt you to slurp.

We are all mere cogs in capitalism’s machine, I suppose, but it’s still a tragedy to see those gears turning out a frozen beverage. Perhaps I never should have started looking into Slurpees and Freezonis and the like. I’d long assumed that greater knowledge makes a pleasure more intense. But to know a slushie only numbs the soul.

In Sunday's New York Times crossword puzzle, constructor Stephen McCarthy embedded a wonderful trick centered on the Star Trek vs. Star Wars debate. For the clue "The better of two sci-fi franchises," either answer works. From the Constructor Notes:

I am a fan of both "Star Wars" and "Star Trek," so it's nice to be able to highlight both (not to mention the friendly rivalry between the two fandoms) in one puzzle.

Before the presidency of Abraham Lincoln, Christmas and Thanksgiving reflected an intense regional divide. Thanksgiving was historically associated with America’s so-called Puritan North and Christmas with the Cavalier South. Lincoln, who was rooted in early Puritan New England on his father’s side and the Cavalier Virginia planting class on his mother’s, combined a deep moral commitment to liberty with a firm sense of honor. He responded to the crisis of the Civil War by redefining Thanksgiving and Christmas as days celebrated not on the basis of sectional identities, but rather in the inclusive spirit of American democracy, which he called “the last best hope of earth.”

[Read: Did religion make the American Civil War worse?]

The farming and harvest festival eventually known as Thanksgiving had its roots in a celebration held by the Puritan Pilgrims of Plymouth Colony in the fall of 1621, nearly a year after the landing of the Mayflower. Thanksgiving was for more than two centuries a northern-state affair, celebrated annually at different times in the mid-to-late fall. In the early 1840s, Sarah Josepha Hale, the editor of the popular magazine Godey’s Lady’s Book, began using her columns to push for nationalizing Thanksgiving and celebrating it on the last Thursday in November. Her writing became more and more impassioned as she witnessed the widening rift over slavery. When division led to civil war, Hale wrote a letter to President Lincoln, emphasizing the urgency of making Thanksgiving “a National and fixed Union Festival” that would offer healing to a torn nation. She told him that by announcing “this union Thanksgiving,” the president could ensure that “the permanency and unity of our Great American Festival of Thanksgiving would be forever secured.”

Like Hale, Lincoln thought that holidays had the capacity to unite people—in his words, “they bring us together, and thereby make us better acquainted, and better friends than we otherwise would be … They make more pleasant, and more strong, and more durable, the bond of social and political union among us.”

During the Civil War, proclaiming religious holidays was one of Lincoln’s main cultural means of encouraging the spirit of “unionism” that the poet Walt Whitman identified as the “hard-pan of his character.” To this end, Lincoln issued nine religious proclamations—far more than any other U.S. president.

He saw Thanksgiving in particular as a powerful impetus to restoring national unity on the basis of human justice. On October 3, 1863, shortly after receiving Hale’s letter, Lincoln declared the last Thursday of November as the day when God would be thanked “as with one heart and one voice by the whole American People,” including “my fellow citizens in every part of the United States, and also those who are at sea and those who are sojourning in foreign lands.” Lincoln asked for “the Almighty Hand to heal the wounds of the nation and to restore it as soon as may be consistent with the Divine purposes to the full enjoyment of peace, harmony, tranquility and Union.”

The next year, continuing his effort to forge national unity on northern terms, Lincoln again set the last Thursday in November as the date for Thanksgiving, prompting The New York Times to remark, “The custom of the New England Pilgrims, at first confined to a few states, has at last, in 1864, assumed the scope and standing of a grand national holiday, which it is hoped, will be permanent and universally observed.” The federally authorized Thanksgiving held on the last Thursday in November became a tradition, and Franklin D. Roosevelt established it as an official American holiday in 1941.

[Read: Thanksgiving, a celebration of inequality]

Through his Thanksgiving proclamations, Lincoln was nationalizing a holiday that by its nature was associated with Puritan New England, the main source of abolitionism. The New-York Tribune noted that “the general adoption of Thanksgiving Day is a striking proof of New England influence.” Similarly, in an article about “A National Thanksgiving,” a Massachusetts paper announced, “Thus the old Puritan festival, so long restricted to the narrow circuit of New England, and derided by the self-styled cavaliers of the South as a relic of early conceit and bigotry, takes on, in this eventful and memorable year and for the first time in our history, a national character.” Lincoln’s Thanksgiving proclamations accomplished for Puritan-based notions of liberty what the Gettysburg Address did for the doctrine of human equality in the Declaration of Independence, merging progressive American ideals with the very definition of the nation.

But if Lincoln brought a largely northern celebration to the South, he also took a largely southern celebration to the North.

Christmas had never taken root in the North. In fact, it had frequently been banned by the Puritans of early New England, who regarded it as a vestige of paganism that had been adopted by the Catholic and Anglican Churches. The Puritans, who fled to the New World in rebellion against these Churches, rejected saints’ days and religious holidays such as Christmas and Easter, pointing out that they were unmentioned in the Bible. Orthodox Puritans argued that the date of Christ’s birth was unknown, and that fourth-century Christians had sacrilegiously taken December 25 from a pagan festival, Saturnalia, that marked the winter solstice. Rejecting this “heathenish” holiday, Puritan leaders in New England did what they could to suppress Christmas celebrations. The Pilgrims’ spiritual leader, the Reverend John Robinson, said that worshippers could not be true Christians as long as they continued “benightedly celebrating Easter and Christmas, for which there was no warrant in Scripture.” Increase Mather wrote in his diary that “men dishonor Christ more in the 12 days of Christmas than in all the 12 months beside.” As the 19th-century historian George Curtis wrote, “The Puritans … frowned on Santa Claus as Antichrist” and viewed Christmas as a relic of “popery.”

The Cavaliers, southern settlers loyal to the Stuart kings, found in Christmas both a religious holiday and a means of legitimizing and preserving the institution of slavery. Slaveholding southerners believed that they were carrying on the old Anglican tradition of a festive Christmas by giving the people they had enslaved alcohol and encouraging wild celebrations. But Frederick Douglass hated the drunken revelry of Christmas, seeing it as a sop contrived by masters to distract from oppression.

During Lincoln’s presidency, though, Christmas took on new meaning. Chiefly responsible for its transformation was the famous German American illustrator Thomas Nast, who created the modern Santa Claus—the jovially pipe-smoking, white-bearded, red-suited night flyer we know so well—and made him distinctly pro-northern and antislavery. Nast, a Lincoln devotee, put his Santa in politically charged scenarios. One of his first distinctive illustrations, on the cover of Harper’s Magazine in January 1863—the month Lincoln issued the Emancipation Proclamation—showed Santa delivering presents to Union soldiers in an army camp. Nast’s Santa, quite literally, embodies the North: He is clad in stars and stripes, surrounded by cheering Union soldiers, and holds in his hand a toy puppet of Jefferson Davis being hanged by the neck—a reminder of the improvised line in “The John Brown Song,” “We’ll hang Jeff Davis from a sour apple tree.”

Lincoln recognized the political significance of such illustrations. “Thomas Nast has been our best recruiting sergeant,” he said. “His emblematic cartoons have never failed to arouse enthusiasm and patriotism, and have always seemed to come just when these articles were getting scarce.” General Ulysses S. Grant, when asked who was “the foremost figure in civil life” during the war years, replied, “I think, Thomas Nast.”

During the second half of the Civil War, the North became more associated with Christmas. An 1863 political cartoon, “Santa Claus Visits Uncle Sam!,” showed Lincoln in a Santa outfit stuffing Union victories—Gettysburg, Vicksburg, Port Hudson, and others—into the nation’s Christmas stocking. The next year, the North’s imminent victory over the South was represented in a picture of the costumed “Santa Claus Lincoln” thumbing his nose at a recumbent, dying Davis.

December 1864 brought a merging of the Christmas spirit and the North’s aims. William Tecumseh Sherman intentionally timed his note to Lincoln about his capture of Savannah, Georgia, to arrive by telegraph by Christmas. Indeed, Lincoln received Sherman’s telegram— “I beg to present you as a Christmas gift the city of Savannah”—on December 25. Lincoln immediately replied, “Many, many, thanks for your Christmas-gift—the capture of Savannah.” Newspapers ran exuberant headlines such as “SAVANNAH OURS. Christmas Gift to the Nation.” The popular magazine Frank Leslie’s Weekly predicted that hereafter “the 25th of December [will] recall the splendid ‘Christmas gift’ of Gen. Sherman to ‘Old Abe’ for many generations to come.” The Thirteenth Amendment was about to work its difficult way through Congress, and Sherman’s landmark Christmas present gave a timely boost to the abolition of slavery.

The American celebration of Christmas, once endemic to the slaveholding South, was now associated with Lincoln and the North. No one saw this more clearly than Nast, whose December 1864 lithograph “The Union Christmas Dinner” showed the tall, dignified Lincoln standing at the open door of a grand dining hall (the northern-controlled nation) and inviting defeated southerners to a holiday feast at a long table. In the picture, northerners occupy the chairs on one side of the table; the opposite side of the table is empty, soon to be filled with southerners who will take chairs labeled with abbreviations of the names of their respective states. Nast made the North’s domination of the holiday very clear. Not only are Lincoln and the seated northerners the hosts of the “Union Christmas,” but the lower-left corner of the engraving has a picture of Confederate generals surrendering to Union ones, while the upper-right corner features an image of the prodigal son returning to his father.

By the end of the Civil War, Thanksgiving and Christmas reached across sectional and ethnic divisions. They were joined by a third holiday, Easter—also minimized in Puritan New England—which took on deeper meaning when Lincoln was assassinated on Good Friday, 1865. In 1868, three years after the war, Godey’s Lady’s Book, which had once made a lonely call for national holidays, could joyously count among America’s holidays “Thanksgiving Day, with its families all over the land gathered together for kindly intercourse; Christmas, with its delightful associations and holy memories; and Easter, best and brightest of all, when peace and good-will are renewed to men.”

The North’s decisive victory in the Civil War helped turn these religious holidays into what Lincoln had said civic celebrations should be: opportunities to strengthen “the bond of social and political union among us.”

In the recent governor’s race in Virginia, Glenn Youngkin scored a huge upset win days after promising to ban critical race theory from Virginia schools. Youngkin is hardly the only Republican calling for school bans. In Texas, Representative Matt Krause sent a letter to school administrators about books in their district. Did they have Ta-Nehisi Coates on their shelves? Isabel Wilkerson’s Caste? How about LGBT Families, by Leanne K. Currie-McGhee? Or any of about 850 other books that might, in Krause’s words, “make students feel discomfort, guilt, anguish, or any other form of psychological distress because of their race or sex”?

Beyond Texas, beyond Virginia, the prospect of banning books and ideas from public schools has GOP strategists smelling electoral blood. House Minority Leader Kevin McCarthy vowed to turn school bans into a winning issue for Republicans in 2022, sketching a “parental bill of rights” to protect kids from troubling ideas about race and sex.

[Zachary D. Carter: The Democratic unraveling began with schools ]

These efforts have a history. Back in the 1920s, the vague term that galvanized conservative angst was not critical race theory but evolution. Conservative pundits at the time seized on a cartoonish misrepresentation of evolutionary science and warned their fellow Americans that “evolution” was nothing less than a sinister plot to rob white American children of their religion, their morals, and their sense of innate superiority.

But although the school bans might have changed some school curricula in the short term, in the long-run, they backfired. Telling parents you don’t want their kids to have the best possible public schools is never good politics. A full century ago, the most effective school-ban campaign in American history set the pattern: noise, fury, rancor, and fear, but not much change in what schools actually teach.

In the 1920s, the idea of evolution wasn’t new. Charles Darwin’s bombshell book about natural selection had been published 60 years earlier. The outlines of Darwin’s theory had become standard fare in school textbooks and curricula, even though the real scientific controversies about the mechanism of natural selection were by no means settled. But the furious campaign to ban evolution had nothing to do with those debates among scientists.

[Read: The evolution of teaching creationism in public schools]

In 1923, T. T. Martin, the “Blue Mountain Evangelist,” preached that “evolution is being drilled into our boys and girls … during the most susceptible, dangerous age of their lives.” Evolution, Martin warned, was not good science but only a plot by “sneering” “high-brows” to inject mandatory atheism into public schools. Martin claimed to have “abundant evidence that the teaching of these text-books is unsettling the faith of thousands of students.”

He never shared that evidence, but he did paint a terrifying picture of the evolutionary conspiracy’s results. Once the “Evolutionists” robbed children of their faith, Martin wrote, they “laugh and jeer, as the rapist laughs and jeers at the bitter tears of the crushed father and mother over the blighted life of their child.”

Martin’s pitch wasn’t only about religion. He framed his fight against evolution as a fight against all manner of modern woes. Supporters of evolution, Martin preached, were not real men; they were “sissy”; they had given up their “Christian manhood.” They were not even real Americans; they were betraying “the spirit of those who came over in the Mayflower,” Martin said, adding, “Where is the spirit of 1776?”

What could anxious parents do if they wanted to keep their children safe from the schemes of atheists and sissies? How could they protect kids from a vision of America that wasn’t focused on sturdy white Puritans and the heroic followers of George Washington? In language that could have come from 2021 and not 1923, Martin told parents to take over their local school boards, to “put on the Board of Trustees only men and women who will not employ any teacher who believes in Evolution.” After that, Martin predicted, seizing control of state legislatures and cramming through anti-evolution laws would be simple.

It was never quite that simple, but the movement to ban evolution from public schools seemed, for a few years, to be an unstoppable political juggernaut. School-board elections became furious affairs, pitting neighbors against one another with accusations of treason and atheism. To give just one example, in Atlanta, William Mahoney, the local leader of the Supreme Kingdom, a Ku Klux Klan offshoot, attacked school-board members and the city’s teachers. He promised to force the reluctant school board to eliminate five teachers on suspicion of teaching ideas that were “paganistic … atheistic … beastialistic … and anarchistic.”

State legislatures weren’t far behind. From 1922 to 1929, legislators proposed at least 53 bills or resolutions in 21 states, plus two bills in Congress. Five of them succeeded. Oklahoma’s 1923 law provided free textbooks for the state’s public-school students, as long as none of those textbooks taught “the Darwin theory of creation.” Florida’s legislature passed a nonbinding resolution in 1923 declaring that teaching evolution was “improper and subversive.” Tennessee was the first to actually ban the teaching of evolution. “It shall be unlawful,” the 1925 law said, “to teach any theory that denies the Story of the Divine Creation of man as taught in the Bible.” Mississippi followed suit, banning in 1926 “the teaching that man descended, or ascended, from a lower order of animals.” Finally, in 1928, anti-evolutionists in Arkansas managed to pass a similar law by forcing a popular vote.

Liberals quaked. In the words of one science educator in 1927, the U.S. had entered its first modern culture war, a pitched battle between two “opposing cultures.” On one side was science, progress, and liberalism. On the other were the “forces of reaction” and “armies of ignorance” with their sights set on “dominat[ing] our public institutions.”

In the furor of these political battles, few paused to examine the actual goals of the anti-evolution movement too closely. Oklahoma’s law, for instance, was at least as much about providing free textbooks as it was about evolution. And Florida’s resolution was purposefully vague, purposefully symbolic. In 1923 Florida, what politician would vote in favor of “subversive” teaching?

[Read: I was never taught where humans came from ]

The bills that did not pass, meanwhile, veered ever further from the actual science of evolution. One early bill in Kentucky in 1922 proposed to ban not only evolution but “Darwinism, Atheism, Agnosticism, or evolution.” As the bill wended its way through the process, lawmakers added provisos: The law would empower citizens to sniff out and report such teaching. School boards would be forced to interrogate any educator charged with teaching evolution within five days. And the ban became broader and more impractical with every new iteration. One Senate amendment, for instance, would have banned “the teaching of anything that will weaken or undermine the religious faith of the pupils” in any public school or college.

Kentucky’s lawmakers weren’t the only ones hoping to ban anything they didn’t like. Across the country, in state legislatures from Delaware to California, conservative lawmakers tried to score political points by banning modern ideas from their public schools. Congress considered a bill in 1926 that was supposedly “anti-evolution” but in fact imposed sweeping restrictions on the content of public schools. At the time, Congress controlled the budget for schools in Washington, D.C. The 1926 bill would have cut the salary of any D.C. instructor caught teaching “disrespect of the Holy Bible, or that ours is an inferior form of government.”

These bills were more about political theater than pedagogical policy. Their claims were so broad and so vague that they would have led only to chaos and confusion in public schools. In West Virginia, for instance, one 1927 bill simply banned any “nefarious matter” from the state’s public schools.

These bills never answered the obvious questions: Who would decide what counted as nefarious? What would a teacher have to say to be considered disrespectful of the Holy Bible? What did it mean to teach that other governments might have better ideas than ours? To be sure, many of these state bills never had much chance of ever becoming law. But Kentucky’s wide-ranging bill failed by only one vote. If it had passed, it would have radically challenged the very idea of a liberal-arts education. What could getting rid of any ideas that could “weaken” a student’s religious faith have possibly meant?

Back then, just like today, no one knew. The anti-evolution movement wasn’t really about banning one specific scientific idea; it was instead a confused and confusing effort to make America great again by purging its schools of science, history, and critical thinking. Movements to ban ideas from public schools were always less about realistic educational policy and more about planting a political flag for a vaguely defined vision of America.

How did the fight over evolution end? Every town and city was different, but Atlanta can offer one example of how frightening the anti-evolution surge could be and how fast it could fall apart. In March 1926, William Mahoney, the anti-evolution leader of the Supreme Kingdom, seemed to have brought the city school board to its political knees.

As the school board prepared to discuss a citywide ban on teaching evolution, Mahoney gathered 2,000 citizens in an open-air rally. A visiting preacher warned the crowd that if the school board failed to ban evolution, “20 years from now there will be no respect for law in Atlanta and Georgia will be a sea of debauchery.” Yet the school board voted down a proposed ban, 9–3. As one member announced, good science was what every “intelligent, educated, and open-minded” citizen really wanted in Atlanta’s public schools. After its humiliating defeat, the Supreme Kingdom fell apart. Its national leader, Edward Young Clarke, became embroiled in a series of sexual and financial scandals, and Mahoney became a local laughingstock.

Nationwide, the anti-evolution movement suffered a less dramatic denouement. Instead of headline-grabbing showdowns and momentous defeats, the movement simply petered out. It became just another distraction that teachers had to deal with. About a decade after the last anti-evolution law was passed in 1928, one survey of thousands of high-school teachers showed that most had simply gone on with their teaching without fuss or bother. Several of them reported that they did not in fact teach evolution, but not because they were concerned about “Christian manhood” or upholding the “Spirit of 1776.” Instead, they were more worried about much more prosaic problems—many reported that they could not teach evolution simply because they did not have enough time in the day.

Certainly, some teachers had been cowed by the fury of the anti-evolution movement. In a 1942 survey of high-school science teachers, one California teacher reported avoiding teaching evolution because “controversial subjects are dynamite to teachers.” Others, however, said they could never be scared away from teaching good science. One respondent from upstate New York, for example, insisted he would carry on teaching evolution. “I’ve had fights,” he said, “but haven’t lost yet.”

Textbook publishers were less willing to fight. The vague outburst of hostility against evolution stymied the publication of textbooks that boldly and freely taught the best modern science. But wary publishers didn’t cower before the anti-evolution mob as much as they pretended they did. They couldn’t afford to.

As the careful work of the historian Adam Shapiro has shown, prominent publishers claimed to have edited out evolutionary content, but many times, they simply didn’t. The best example might be the case of George Hunter’s Civic Biology. This textbook was at the center of the famous Scopes Trial in 1925. After the furious wave of anti-evolution bans had passed, the publisher offered a new edition, supposedly free of objectionable evolutionary content. In fact, however, the “evolution-free” edition was almost exactly the same as the old edition. The publisher merely removed the word evolution and replaced it with similar words such as development.

And no one objected. As Shapiro found, most of the conservative watchdogs appointed by anti-evolution lawmakers gave new textbooks the most cursory of glances. If publishers edited their indexes and tables of contents, if they removed the word evolution—the word itself, not the idea—they could avoid expensive revisions to the text. As a result, many textbooks kept their scientific treatment of evolution the same.

Over time, even successful legal bans revealed their own inherent weaknesses. In Arkansas, for example, by 1965, science teachers were required to use state-approved textbooks that taught evolution, even though the state’s 1928 ban was still officially in effect. It was an absurd situation, and one brave teacher finally took the case all the way to the U.S. Supreme Court. The Court ruled in 1968 that the state’s ban on evolution violated the Constitution.

Years before that, however, even in states like Arkansas that had legally banned evolution in the 1920s, people had quietly agreed that the ban violated a more fundamental requirement of public schools. Bans on modern ideas only hurt schools and students, they concluded. In the long run—and, as in Atlanta, even in the short run—the call to ban evolution could not overcome parents’ insistence on the very best modern public schools for their children, schools free from the dictates of what one Atlanta school-board member called “error enshrined in popular belief.”

Back in the 1920s, the effort to ban evolution was not really about the science of evolution. It was instead an attempt to bolster political careers with sweeping but ultimately meaningless gestures. The confusion and vagaries of the 1920s bills were not accidental. Voters might not have known what scientists meant by terms like natural selection, but they knew what politicians meant when they took a stance against “nefarious matter” and against radical teachers who supposedly taught children that “ours is an inferior government.”

But the bans failed to change many textbooks, failed to change many classrooms, and failed even to change the course of many political careers. Politicians willing to stand in the schoolhouse door to keep out troubling ideas will not be willing to stand there forever. Sooner or later, the cameras will leave, and parents will demand that schools give their children the best available education.