There’s always a general vagueness about just how it works, but that the the Overton Window exists is taken as read by a lot of people, and I’m sure most people who cite it believe it’s an idea that’s been discussed by academics over many years and has been rigorously tested and proven to be correct. You might think that, but you’d be wrong. Here’s a search for it with Google Scholar, which indexes millions of pieces of academic research and writing, which brings back no serious academic references to it. It does get mentioned in a few Glenn Beck books, some obscure libertarian pamphlets and in publications from the think tank it emerged from, but no serious academic attention has been paid to it.
Why is that? I’d propose that the most obvious explanation is that the Overton Window isn’t actually a theory, it’s just a vague assertion. See, for instance, this article about it (pdf) which starts from the assumption that it exists and goes from there. Any actual theory of political science has to be testable, and if the Overton Window was a theory it would come with a set of testable predictions about public opinion and how it shifts over time. It would also come with justification for some of the simplifying assumptions it appears to be based on, most notably that all the policy options for a certain issue can be placed on a straight line. None of that exists for the Overton Window, and none of its advocates appear to have put any effort into trying to prove it, preferring to assert its truth without testing.
I’ve written before about Zaller’s Receive-Accept-Sample model of public opinion, and I think it provides an interesting counterexample to the Overton Window in that it’s a genuine theory which has been thoroughly tested and shown to make accurate predictions about how public opinion works. However, as it’s slightly more complex than ‘you can do some things, you can’t do others, but if you want to do the others then sizeable donations to our think tank might help make them possible’ it doesn’t get mentioned much by supposed experts on public opinion in the media.
This is a shame, because I think Zaller’s work on how elite opinion leads public opinion (in The Nature and Origins of Mass Opinion) is a much more useful concept than talk of windows. Zaller shows that when elites (politicians, media and other opinion formers) are generally agreed on an issue, public opinion follows suit. Public opinion on an issue only begins to shift when elite opinion begins to divide and differ. To use Zaller’s example (though there are many others in the wider literature), American opinion on the Vietnam War was mostly in favour of it until newspapers and politicians started raising questions about it, and then it began to fade. (That’s a bit of a simplification, but the key point is that public opinion tends to follow elite opinion, not vice versa) If there’s not an elite consensus, then public opinion will tend to cover a much wider spectrum.
Public opinion is a much more vague and nebulous thing than an idea like the Overton Window gives credit for. In truth, most people have what Converse called ‘nonattitudes’ to most issues: they’re capable of giving an opinion on something if asked, but that opinion is often completely random based on what they’ve seen and heard recently rather than a fixed and carefully considered outcome of rational thought. Trying to analyse something so amorphous using concepts that are fundamentally weak is almost a guarantee of misunderstanding what’s actually happening. Public opinion can be shifted much more quickly and much more widely than people think but the key to doing that is finding messages that reach people and become part of their considerations, not obsessing over the location of mythical windows.