Men walk near a reinforced section of the U.S.-Mexico border fence as seen from Tijuana, Baja California state, Mexico on Thursday. (AFP/Getty Images) (Guillermo Arias/AFP/Getty Images)
Paul B. Sturtevant is editor-in-chief of The Public Medievalist and author of the new book "The Middle Ages in Popular Imagination."

As the fight over funding for President Trump’s wall has dragged on, the conversation has taken an odd turn. The president’s critics and Democratic opponents have been slamming his proposal for a wall on the border with Mexico as “medieval” for years. In September 2017, Senate Minority Leader Charles E. Schumer (D-N.Y.) called it “a medieval solution to a modern problem. A ‘Game of Thrones’ idea for a world that is a lot closer to ‘Star Wars.’ ” In recent weeks, Democratic leaders such as Rep. Hakeem Jeffries (N.Y.) and Sen. Richard J. Durbin (Ill.) have joined the chorus slamming the idea as “medieval.”

But over the past week, the president has leaned into the idea of a “medieval” wall. At a bill signing in the Oval Office last Wednesday, he said: “They say it’s a medieval solution, a wall. It’s true, because it worked then, and it works even better now.” Since then, he’s continued to reiterate this talking point: that “medieval” means “good.”

Both Trump and Democratic leaders are misconstruing history, and that is the point. The medieval ideas invoked by both sides reveal much more about their current values than they do about medieval history itself. Understanding that this is a dog whistle is crucially important.

Schumer and other critics of the wall use the term derisively. When they say something is “medieval,” they are evoking the outdated image of the “dark ages,” where everyone was muddy, bloody, backward and superstitious. In doing so, they are appealing to the false but widely shared idea that nothing good came from that Middle Ages, so associating anything or anyone with that era dirties them by association.

Of course the Middle Ages were never as nasty as all that. But the image has remained with us despite decades of scholarly pushback because it is useful for us to have a “dark age.” Looking back on a dark age allows us to feel superior — technologically, culturally, religiously, intellectually — to those who came before us. It offers us a beginning point of Martin Luther King Jr.’s famous “arc of the moral universe” so we can pride ourselves on how much it has bent toward justice. And as a bonus, it offers us an easy way to dehumanize our opponents and trash their ideas.

But when Trump calls his wall idea “medieval,” he means something very different.

On the surface, his recent remarks over the past week imply he is trying to express something like “tried and tested,” most recently comparing the wall to the technological marvel that is the wheel. But then why, of all the possible terms he could have used, did he say “medieval”?

It’s because for a significant portion of the American public, especially among his base, being “medieval” is not a bad thing. Instead, it’s aspirational. White nationalists have long deployed toxic interpretations of the medieval world — particularly Viking, Crusader and Celtic histories — to present themselves as heroic holy warriors.

A love affair with the Middle Ages has been at the heart of European nationalism since the 18th and 19th centuries. But in more recent times, far-right nationalists have used nostalgia for the Middle Ages to undergird their pseudoscientific theories about race and justify their murderous regimes. The Nazis twisted research on medieval Germanic and Nordic cultures to present a heroic “Aryan” past to support their idea of a “master race.” Neo-Nazis, including the what’s known as the alt-right, have followed suit. In 2016, the American National Socialist Movement (a neo-Nazi party, not to be confused with actual socialists) adopted a Viking rune as its symbol, since the swastika bore too many negative connotations.

In the same vein, far-right Christian nationalists and Dominionists employ Crusader imagery. But only some of those who use Crusader imagery do so to express extreme Christian ideology. Others, like Norwegian terrorist Anders Breivik (who styled himself as a member of the Knights Templar), use the Crusades as an expression of violent Islamophobia. Under Trump, this use of history has mutated into a broader xenophobia and racism that also regularly targets Latino people and, as seen at the incident at the Lincoln Memorial on Friday, American Indians.

Online meme culture has made this use of medieval imagery viral. In online campaigns, right-wing trolls regularly deploy memes of Crusaders to bolster their arguments and mock their opponents. For example, supporters of far-right wing Brazilian President Jair Bolsonaro regularly share “Deus Vult” memes — a reference to a battle cry of the First Crusade — on social media. Closer to home, at the 2017 white nationalist rally in Charlottesville, we saw medievalesque weapons swung and banners flown sporting images drawn from Viking, Crusader and Celtic histories.

But even among those of Trump’s supporters who (unlike Iowa congressman Steve King) are not overt white nationalists or white nationalist sympathizers, the idea of a “medieval wall” evokes a distinctly different image from Schumer’s.

Those who celebrate the wall want America not to be Ronald Reagan’s “shining city on a hill” but a fortified castle protected by dragons and a moat. The rhetoric of this administration that turns groups of poor refugees into “caravans” of “invaders” and “terrorists” contributes to this sense that America is under siege. And some Americans want to feel under siege, because it allows them to envision themselves as righteous heroes.

They like the medieval wall not because it will be effective; pundit after pundit has pointed out that it can be conquered by the equally medieval technologies of “the saw,” “the ladder” or “the shovel.” They like it because of what it symbolizes. In this worldview, “medieval” is not a slur; it’s part of constructing a new medievalesque ideology of Castle U.S.A.

For Castle U.S.A., the “medieval wall” is a symbol that America is actively defending itself from those on its southern border. It is a symbol that those on one side are the righteous defenders of a glorious empire, and those on the other are uncivilized or inhuman: barbarians at the gates.

Politicians would be far better off grappling with the reality of the proposals before them, instead of using fantasies of the past to score political points. But so long as Schumer or other critics continue deride Trump’s wall as “medieval,” it is important for them to understand the sort of white nationalist fantasies they are inadvertently playing into. In the case of Trump, and some of the public, their Middle Ages is not a dark age best consigned to the dustbin of history but, rather, a source of strength and inspiration for the whites-only battles they want to wage.