Ideas take on a life of their own. The only way to control an idea is to keep it to oneself. That might be personally edifying, but an idea kept within the confines of a single mind will do little to change the world. And Joe Overton was all about changing the world.

He had a 43-year run that ended 20 years ago today, on June 30, 2003. I’ve spoken and written of his sudden and tragic death hundreds of times, yet it is never a dispassionate statement of fact. The shock and trauma of losing Joe remains palpable, a faint echo of the night his brother Scott called me with the news and asked me to go with him to tell their mother.

A generous reader may indulge my personal remembrances on this anniversary. But that’s not why I decided to write. Joe was a font of ideas but one in particular took on an outsized life of its own after we, his colleagues, released it into the wild. The Overton Window has become part of the public policy lexicon in ways no one predicted.

The Overton Window is a model of policy change, and Joe was the first one to articulate it to me. In his view, ideas become policy only after they move from being unthinkable notions that cannot become law to becoming popular ideas that elected officials are eager to ratify into law. This can take days, or decades. The purpose of a think tank, and other “secondhand dealers in ideas” to use F. A. Hayek’s term, is to make the case for ideas that are politically impossible until they become politically inevitable. A window of public opinion shifts to surround some ideas and to leave others behind. Think tank research, analysis, testing and debate can shift this window.

Joe Overton simply wanted to describe what think tanks do and explain why someone might support one. He called his model the “Window of Political Possibilities.” I have his original, longhand notes in a folder he labeled “Shifting Windows.” Together, he and I were to create a card stock brochure with an actual, sliding window to illustrate the change in the range of politically acceptable ideas on any topic at hand. The brochure proved expensive to produce and we created nothing but a handmade prototype. The concept, however, became part of the curriculum of a think tank school we taught beginning in the 1990s.

I taught Joe’s window concept following his death. We named it “The Overton Window” in his honor, and that was when his idea escaped into the wild. The mid-to-late aughts were the first age of the blogs. One of our think tank trainees, Josh Treviño, blogged about the Overton Window from his hotel room the very night he learned of it. Josh was read by activists across the political spectrum, and they amplified, challenged and opined on Josh’s description. The spread of Joe’s eponymous idea accelerated from several dozen people a year to hundreds or thousands a day.

What hath Josh wrought? He scaled the transmission of the Overton Window idea by blogging about it. Henceforth came a flurry of citations and usages of the term in the mainstream political press, many of them just plain wrong. But that is not surprising, since the source material was a few notes sketched out in longhand in a file drawer in my office, verbally related to Josh Treviño and other think tank trainees via my PowerPoint presentation, and then blogged to the world. There was no grand, underlying, academic theory to which anyone could refer.

Joe’s insight was simply that lawmakers can’t enact whatever policies they please. They mainly enact policies they perceive as already popular, or at least acceptable, with the people they represent. Think tanks (and others) profoundly influence public opinion on policy, ideally (for them) shifting opinion in the direction they desire.

Any Google search of “Overton Window” yields descriptions ranging from just plain wrong to pretty good. I recommend a New York Times piece by Maggie Astor (where I am the interview subject) and a radio episode of “On the Media” (where I am again the interviewee).

Joe Overton’s model of policy change is now embedded in the parlance of mainstream political journalism. I wonder what else he might have contributed to our political discourse had he lived longer, but I am grateful to be part of his legacy.

Permission to reprint this blog post in whole or in part is hereby granted, provided that the author (or authors) and the Mackinac Center for Public Policy are properly cited.