The US Constitution did not establish a clear division of responsibilities between the national government and state governments, so the distribution of policymaking authority is subject to constant renegotiation and debate. When national lawmakers introduce policy initiatives that implicate the states in important ways, why do state leaders sometimes respond with strong support and other times with indifference or outright hostility? Moving beyond the conventional story that state officials simply want money and autonomy from their national counterparts, this book explains how the states' responses over the short, medium, and long term are shaped by policy design, timing, and the interaction between the two. Reaching across different historical eras with in-depth case studies of policies such as Superfund, the No Child Left Behind Act, and the Patient Protection and Affordable Care Act, the book shows how federalism has influenced, and continues to influence, the evolution of American public policy.