Want to understand American creationism? Then don’t dig into Charles Darwin or even Bill Nye. The key to American creationism isn’t science, not even its peculiar “zombie” science. No, to understand radical American creationism, we need to look instead to poetry and the fundamentalist impulse.

Here’s the latest: today’s leading radical creationist Ken Ham recently defended his young-earth position against charges of flat-earthism. As Ham bemoaned,

now it’s not just atheists arguing the Bible teaches a flat earth—it’s some Christians, too, who’ve sadly fallen for flat-earth arguments and now believe that’s what the Bible teaches. But does it?

No, it doesn’t. Now, flat earthers will frequently bring up poetic passages, such as verses from Psalms or Job, and say those verses teach a flat earth because phrases like “ends of the earth” or references to a setting sun appear. But those passages are poetry—by definition poetry is filled with literary devices such as metaphors, similes, and figures of speech. The biblical text is meant to be interpreted naturally, according to the genre. And poetry is clearly intended to be understood within the context of abundant literary devices that are not meant to be taken so woodenly and literally (i.e., God does not literally lie us down in green pastures as per Psalm 23:2).

For those who know the history of American creationism, Ham’s use of the “poetry” defense must seem either brutally cynical or woefully ignorant. Here’s why: Back in the 1950s, fundamentalist Protestant scholars tried to move away from Ham’s preferred sort of radical young-earth creationism. They wanted to remain creationists, but they didn’t want to be bound to scientifically outlandish notions such as a 6,000-year-old earth or a literal world-wide flood.

How did they interpret the creation passages in Genesis? You guessed it: as poetry.

Most influentially, Bernard Ramm argued in his 1954 book The Christian View of Science and Scripture that simple young-earth creationism made a huge theological mistake. As Ramm wrote,

If the theologian teaches that the earth is the center of the solar system, or that man first appeared on the earth at 4004 BC, or that all the world was submerged under water at 4004 BC and had been for unknown millennia, he is misinterpreting Scripture and bringing Scripture into needless conflict with science.

When the Bible describes creation, Ramm argued, it was speaking poetically, in popular, accessible language. Such language, Ramm thought, did not “theorize as to the actual nature of things.” Rather, it explained God’s role as a personal, engaged Creator in poetic language that people everywhere could understand.

For radical creationists, the problem with evolution is what it supports…

The modern American radical-creationist movement was born as an attempt to directly refute Ramm’s ideas. John Whitcomb Jr. and Henry Morris set out in their blockbuster creationist hit The Genesis Flood to prove that Genesis was not poetry, but history.

As always, though, poetry is in the eye of the beholder. How were conservative evangelicals supposed to choose where to draw the line? How were they supposed to decide if talk about a flat earth was meant to be read poetically or literally? Or passages about a world-wide flood? Or the age of the planet?

In the end, the answers came down to something besides science or even theology. For Whitcomb and Morris in the 1960s and 1970s, or Ken Ham today, insistence on a literal young earth and literal world-wide flood is not a scientific decision or a theological one, but rather a very popular kind of draw-the-line-ism, a fundamentalist promise that traditional beliefs must be protected at all costs.

For example, when John Whitcomb Jr. and Henry Morris made their first case for radical young-earth creationism, they insisted that there were only two ways to see the world—young-earth creationism or “evolutionism.” On the creationist side stood Jesus and the Scriptures. On evolution’s side were only “ancient idolatries or primitive animism or modern existentialism or atheistic communism!”

Supporting evolution, for Ken Ham, means supporting abortion and homosexuality.

Throughout his long career, Henry Morris insisted that only a rigid, literalistic, radical creationism stood between true religion and a host of pernicious ideas. In The Long War Against God, for example, Morris warned that a poetic reading of Genesis would mean an endorsement of “premarital sex, adultery, divorce, and homosexuality” as well as ”Unrestrained pornography. . . . [and] Prostitution, both male and female.” Don’t forget, Morris warned, that “evolutionary thinking” lead to “abortionism.” And the Holocaust. As well as, presumably, cannibalism, not to mention “the modern drug crisis (rock music, peer pressure, organized crime, etc.)”

When Henry Morris insisted on reading Genesis as literal rather than poetic, he wasn’t making a theological statement. He was not making a scientific statement. Rather, Morris was appealing to America’s fundamentalist impulse, the desire of many conservative Christians to draw the line somewhere.

For Morris and his erstwhile protégé Ken Ham, the threat of evolution isn’t really theological or scientific. Rather, as Ham never tires of repeating, evolutionary thinking is the foundation of a host of modern social ills, from abortion rights to LGBTQ rights; from youthful disrespect to internet pornography.

I can’t help but wonder if Ham is aware of the long history of his poetry defense. Does he know that Bernard Ramm used the same argument against his mentor’s radical young-earth beliefs? Does Ham just not care? Or, rather, does he understand that his followers don’t really care about science or theology, they are just looking for someone to tell them where to draw the line, where to take up a fundamentalist defense of traditional values?