When I was in grad school, involved in the graduate chapter of InterVarsity at Duke, we spent a lot of our time worry about how Christians should respond to "postmodernism." 20th-century evangelicalism had invested itself pretty heavily in a kind of Enlightenment rationalism, and in the 90s many evangelical intellectuals were realizing that it was time for a course correction. And Duke in the 90s was a center of postmodernism. You couldn't walk down the corridor without hearing someone say "Derrida" or "Foucault." Meanwhile, out in popular conservative Christian culture, "post-modern" was a deadly slur. Good Christians were supposed to believe in absolute, unchanging truth.
That rhetoric is still with us, of course, but "postmodern" has more and more come to be merely a slur used by conservatives with little understanding of its meaning. When I taught at Huntington University, one parent wrote to the religion department asking us how we interpreted Genesis 1 (with the strong implication that he would not be sending his remaining ten homeschooled children to our institution if we gave the wrong answer). In the correspondence that ensued, what struck me about this gentleman was his apparent conviction that belief in theistic evolution was "postmodern." I tried to explain to him that I believed in evolution precisely because I believe in facts and evidence and that science reveals truth about the world--not very postmodern beliefs at all.
Creationism is, in fact, a good example of a growing phenomenon that I think needs to be labeled "right-wing postmodernism." When I visited the Creation Museum in northern Kentucky a few years ago, I was struck by the combination of technological wizardry and utter cynicism about science. While the museum claims to present evidence, most of it is designed to work on people's emotions and imaginations and to tear down their confidence in the scientific method. The Creation Museum rests on the assumption that there is indeed absolute truth, found in the Bible, and that merely "human" methods cannot give that truth. Thus, they should always be treated with skepticism.
And of course it's true that all human methods are fallible. There's a lot of truth to postmodern challenges to Enlightenment ideas of science--I've been very influenced by Thomas Kuhn, myself. But the rhetoric of radical postmodernism, as it's filtered down into pop culture, gives the impression that all truth claims are nothing more than rhetoric serving some ulterior purpose. And this turns out to be a point of view that actually fosters firm beliefs that are immune to rational inquiry. The acid of universal relativism eats away at the tentative, carefully formulated beliefs of critical reason far faster and deeper than at the firm dogmas of fundamentalist religion.
The election of Donald Trump represents the triumph of right-wing postmodernism. Millions of Americans who think of themselves as conservatives and claim to believe in absolute truth have voted for a "post-truth" political agenda. Trump's flagrant falsehoods are defended as rhetorical excesses, and any criticism of him is dismissed via the genetic fallacy. Over and over again, Trump supporters move the discussion from evidence and issues to the corrupt power structures that allegedly lie behind any opposition to Trump. There are some exceptions who try to make rational arguments for Trump (Dave Armstrong, for instance), but even they speak loudly about the need for facts and evidence only to discount any evidence that they don't like. I hear, even from Dave, a lot more denunciations of the other side's lack of attention to the evidence than I do any actual treatment of the evidence.
I get that none of this is new, and certainly one can find examples on all sides of the spectrum of people unwilling to listen to evidence that doesn't fit their biases. But the extent to which self-proclaimed conservatives are willing to disregard any serious engagement with evidence and reason strikes me as new. And frankly I think a lot of the blame rests on the shoulders of the "real" postmodernists--the sophisticated academics who sneered for years at the idea of objective truth. Conservatives have, effectively, chosen to take them at their word. And they are playing the game more ruthlessly and effectively than the liberals ever did.