This essay was presented at a conference recognizing the centennial of the publication of Charles Beard’s An Economic Interpretation of the Constitution. It advances two arguments. The first is that Beard’s work is an early example of what I am calling “Progressive historiography,” a perspective that dominated the American historical profession from the early twentieth century through the 1960s, and which had certain defining characteristics, which are set forth in the essay. The second is that the principal explanation for why Progressive historiography retained its influence for so long is that it was a version of “winners history,” portraying the course of American civilization as a series of contests between entrenched elites and advocates of political, economic, and social leveling, all of which were eventually resolved in favor of the levelers. As such Progressive historiography simultaneously contained a critical posture toward established powerholders and an optimistic spin on the course of history that made it intuitively attractive to many persons entering the historical profession in the twentieth century.