A dictatorial regime regularly lashes out with hysterical war propaganda and threatens to rain destruction on its neighbors. It regularly inveighs against American imperialism, and in return, American analysts regularly discuss preventive strikes against the country.

Then, with little warning, it conducts a nuclear test. Americans from all walks of life remember that day vividly. Their lives—indeed, the world—changed forever.

It was May 25, 2009. Don’t you remember?

That, of course, was the day the erratic, bizarre government in North Korea managed to successfully test a nuclear device. But the world didn’t end.

South Korea’s neighborhood got a bit worse, although the North Koreans already had the ability to kill tens if not hundreds of thousands of people in Seoul and elsewhere with artillery tubes lined up across the border. U.S. policymakers had a worse headache to deal with at the 38th Parallel than they did the day before. But not much else changed. Despite Graham Allison’s promise that the test would “trigger a cascade of proliferation in its neighborhood,” it did no such thing.

All of this seems germane to the discussion over Iran. But perhaps most relevant is the fact that the much-predicted nuclear cascade failed to materialize.

Speaking last week at Davos, Henry Kissinger made this comment as to why Iran must not achieve a nuclear capability:

The danger is that we could be reaching a point where nuclear weapons would become almost conventional, and there will be the possibility of a nuclear conflict at some point… that would be a turning point in human history.

Jeffrey Goldberg reads this to mean that “a nuclear arms race in the world’s most volatile region leads to a kind of quick-draw, launch-on-warning approach by multiple nations, ending in an accidental conflagration.”

This is hardly a new fear, and it isn’t just President Kennedy in 1964 noting how he was “haunted by the feeling that by 1970, unless we are successful, there may be ten nuclear powers instead of four, and by 1975, fifteen or twenty…” My colleague John Mueller and Frank Gavin both catalog the embarrassing track record of false positives in predicting tipping points, cascades, chains, waves, avalanches, et cetera. Their bibliographies are full of embarrassingly wrong predictions—full enough that people ought to be chastened and reconsider just throwing around similar assertions as though they are obviously true.

As William C. Potter and Gaukhar Mukhatzanova make clear, though, “Although proliferation projections abound, few of them are founded on, or even informed by, empirical research and theory.” Perhaps that’s why we keep getting it wrong.

A nuclear Iran would have negative consequences, no doubt. I know a lot of people who think a nuclear Iran would hardly be “a turning point in human history,” but I don’t know of anyone other than Kenneth Waltz who believes that on net a nuclear Iran would be a positive thing. Not one person.

But if people are going to hang the argument that Iran must be prevented from going nuclear—at any cost, including America launching another war in the Middle East—on the idea that Iran would precipitate a proliferation cascade, they would do well to read history and theory to figure out why their forebears were uniformly wrong on this question.