Political actors are a diverse lot, animated and engaged by the prospect of change. Operating inside and outside the government, they are out to instigate change or inhibit it, to promote or deflect it, to channel or absorb it. Their interactions keep the American polity in a perpetual state of development, rendering it always to some degree unsettled. In the past, the study of American political development has treated political institutions and ideas as disembodied subjects. In Formative Acts, leading scholars in the field seek to refocus the debate on the political agency of...