The Overton Window is a fairly popular concept on Lemmy, and I haven’t the faintest idea why.

It’s easy to see why the Overton Window holds such appeal. For one thing, it offers a universal theory of change in an age of polarization and fracture. While Trump and the UK Independence Party pull right, and Sanders and Corbyn pull left, Overton’s concept suggests that the mechanism of change is the same. For another thing, it has the virtue of simplicity: Overton did little more than repackage the basic negotiating principle that if you ask for a lot, you will likely get more than if you ask for a little. And although the window offers a theory of change, its central element—the window itself—actually describes the norm from which reality has deviated. Zeynep Tufekci worries in The New York Times that Trump “voices truths outside the Overton Window,” while the British writer Sam Leith speculates that Corbyn may have positioned his party “dangerously far from the centre of the Overton Window.” The window serves as shorthand for the erstwhile consensus. Viewing politics through the Overton Window reinforces liberal notions about the moderate center, even as that center ground erodes.

For conservatives, by contrast, the Overton Window has always been about strategy. Though Overton himself never committed his most influential idea to paper, his Mackinac Center colleague Joe Lehman continued his work after Overton’s death in 2003 at age 43. Lehman not only coined the term “Overton Window,” he weaponized it, setting up training sessions on the concept for other right-leaning think tankers. The term filtered into the conservative blogosphere in 2006, when Josh Trevino enthused about the window as a tool for the right. “Step by step, ideas that were once radical or unthinkable—homeschooling, tuition tax credits, and vouchers—have moved into normal public discourse,” Trevino declared. “The conscious decision to shift the Overton Window is yielding its results.”

The concept did not reach a wider audience, however, until Glenn Beck cast Overton’s ideas as the bogeyman in his 2010 best-seller, The Overton Window. The villain of Beck’s tale is Arthur Gardner, an aging PR guru who plots to use the Overton Window to foist his own objectives (“criminalize dissent,” “reinforce dependence and collectivism”) on an unsuspecting and gullible public. In his afterword, Beck urges readers to watch out for manipulation in their own lives and to set their own priorities.

While Beck shared Overton’s libertarian ideology, he was wary of the window as a strategy for change, imagining a totalitarian left that could hijack it. Its elitist overtones also stuck in his craw: An early champion of the Tea Party, Beck preferred to extol the power of the American people, whereas Overton largely sought to influence policy-making from the top down by “educating lawmakers and the public.” At one point in his novel, Beck takes a veiled swipe at the somewhat otherworldly Mackinac Center, which was founded on an island in Lake Huron: Arthur Gardner’s son boasts that his father “stole the concept” of the Overton Window “from a think tank in the Midwest.”