This paper evaluates why amendments to the U.S. Constitution are more likely to occur at some times but not others. Specifically, we consider whether constitutional reform follows the same pattern of punctuated equilibrium as other policy areas (Baumgartner and Jones 1993; see also Schrad 2007). We conduct an individual-level examination of amendment introductions and an aggregate-level study of amendment proposals. In both analyses, we test political, legal, and social predictors of constitutional reform. For example, we examine whether more amendment activity occurs when one party holds stronger congressional majorities or when polarization does not prevent the formation of cross-party coalitions (Stohler, Bateman, and Woodward-Burns 2022). We also consider the effect of exogenous shocks, like war or economic decline, which may create a need for amendments (Elkins, Ginsburg, and Melton 2009). Similarly, we expect the Supreme Court’s use of judicial review can create backlash that stimulates amendment demand (Clark 2010). Where we depart from most prior studies is our hypothesis that the effect of the Constitution’s amendment rules varies based on the country’s civic connectedness over time (see Blake et al. 2023). We predict amendment introductions and proposals will be higher at times within American history when aggregate-levels of social capital are higher.