Why Our Postwar “Long Peace” Is Fragile

You could be forgiven for balking at the idea that our post-World War II reality represents a “Long Peace.” The phrase, given the prevalence of violent conflict worldwide, sounds more like how Obi-wan Kenobi might describe the period “before the dark times, before the Empire.”

And yet, the “Long Peace” has been a long-argued over hypothesis about the relative absence of major interstate conflict since 1945: Have mechanisms like nuclear deterrence, democratization, economic pacts, and international organizations like the United Nations really fostered an enduring trend of peaceful co-existence, or is this just a statistical fluke—a normal interlude of relative calm before another global-scale conflagration?

“This debate has been difficult to resolve because the evidence is not overwhelming, war is an inherently rare event, and there are multiple ways to formalize the notion of a trend,” Aaron Clauset, a computer scientist at the University of Colorado, Boulder, wrote in a  last year. “Ultimately,” he goes on, “the question of identifying trends in war is inherently statistical.” Which is why he took a deep dive into the data collected by; it has, among other things, information on the onset years and battle deaths (civilian casualties excluded) of 95 interstate conflicts between 1823 and 2003.