History can be a good friend of confirmation bias. We often look to the past for lessons that support beliefs that we already have instead of the ones best supported by a deep analysis of the evidence. For most of today’s pundits and those academics who use the past to imagine the future, the origins of the First World War generally present one of two sets of “lessons.” The first, taking its cue from a recent best seller, characterizes the leaders of that age as “sleepwalkers” who were unusually incompetent and out of their depth. A second set of lessons argues that a presumed similarity between our times and the years prior to 1914 makes conflict today more likely, or even inevitable. These “lessons” need nuance and historical context if they are to provide any insights for today’s policymakers.