The term “reform” conveys a tension between constraint and possibility. The prefix re- suggests familiarity and recursion, just as the root form denotes structure, whether institutional or ideological. And yet “reform” also promises an improvement of circumstances or a mitigation of harm. This optimistic undercurrent requires that reformers not simply deride the existing order but propose alternatives. And to the extent that the term calls for a realignment of established elements rather than obliterating what exists and starting over, “reform” can seem less alarming—but also more tepid—than “radicalism” or “revolution,” even as it suggests greater political engagement than “benevolence” or “charity.” That said, scholars have shown that “reform” cannot be neatly distinguished from those other terms (Bergman and Bernardi 2005; S. Ryan 2003). In the nineteenth-century United States, when “reform” enjoyed wide circulation as a generic descriptor of individuals and movements, its meanings shifted depending on the social and political commitments of the author. Most who called themselves reformers described their work as benevolent, even when they called for structural change rather than direct dispensation of aid, while opponents of particular reform movements characterized their adherents as radicals committed to undermining national stability. As these contestations suggest, reform emerged as...