A 40-year-old person living today would remember one amendment during the course of her lifetime—the 27th Amendment, which, despite being relatively non-salient, took over two centuries to be ratified. By contrast, a 40-year-old person living in 1940 would have seen six amendments added to the Constitution, and many of these were ambitious reforms.  The rules for amendment have remained the same, so why then and not now?

We begin to answer this question by describing the contours of American constitutional development.  Constitutions are policy documents, and timing of US constitutional amendments mirrors the patterns of other policy issues: a punctuated equilibrium (see Baumgartner and Jones 1993).  The harder question for students of public law and public policy alike is: what causes these shifts between constitutional stasis and change?  One might think that the explanation lies in the partisan or ideological landscape of Congress and state legislatures. Parties win elections after promising to redefine the prevailing image of crucial policies. And when one party dominates Congress, they can more easily overcome the transaction costs imposed by Article V. It might also be the case that constitutional amendments are more likely to occur following exogenous political shocks, like economic decline, military conflict, or spikes in the number of statutes struck down by the courts.  More recent scholarship suggests that social capital mitigates the transaction costs imposed by amendment rules (Blake et al. 2024).

We analyze data from each stage of the amendment process: aggregate-level and individual-level forces that influence the introduction of amendments in Congress, aggregate-level determinants of Congress proposing amendments, and aggregate-level factors shaping the ratification of the Equal
Rights Amendment (ERA). The partisan and ideological makeup of Congress and state legislatures also play only limited roles.  We find more consistent evidence that social capital affects amendment introductions in Congress, proposals by Congress, and ratifications by the states.