With the victory of Donald Trump in the 2016 United States presidential election, populists have come to power in the US for the first time in many years. However, US political scientists have been flat-footed in their response, failing to anticipate or measure populism''s impact on the campaign or to offer useful policy responses. In contrast, populism has long been an important topic of study for political scientists studying other regions, especially Latin America and Europe. The conceptual and theoretical insights of comparativist scholars can benefit Americanists, and applying their techniques can help US scholars and policymakers place events in perspective.