All kinds of peoples, previously marginalized in favor of the actions and thoughts of elite policy makers, now fill foreign relations histories. African Americans, Native Americans, Asian Americans, women, workers, and many others have been shown to be indispensable—if informal—diplomatic assets. And yet, diverse as this cast of characters has become, notice one thing they share in common: their adulthood. It is as if human experience with foreign affairs only begins with the age of majority. What might be gained once we appreciate the influence of young people, as both audience and agent, in the long history of America's entanglement with the wider world?