This book describes how conservative state-level officeholders, including governors, attorneys general, and secretaries of state, mounted a major challenge to the Obama Administration and federal power more generally. The opportunity for this challenge to federal power arose from the conjunction of several processes: marked growth in executive power at both the national and state level; shifts in administrative law doctrine friendly to state litigation; and high party polarization that yielded regularly divided national government but single party dominance of state governments. Conservative executive officials cooperated across states in litigation and through various administrative practices; they also adopted a notably uncooperative, conflictual stance in their relations with the Obama Administration. Through chapters examining multistate litigation, new uses of interstate compacts, and new elections administration practices, this book shows that state executive officeholders have used an innovative combination of means to successfully pursue a familiar set of conservative policy goals. A chapter on the small government experiment in Kansas shows that this activity is not a crudely anti-government stance, but rather a particular program of reform grounded in a sophisticated understanding of law and modern administrative institutions. The concluding chapter shows that the domestic agenda of the Trump Administration is substantially a continuation of this earlier state-level activity, and that liberal state officeholders have been quick to emulate new conservative strategies. The likely result is a rearranged, conflictual American federalism in which the states are more important and powerful than they have been since the Progressive Era.