The authors argue overlapping intergovernmental authorities explain much of the complexities in U.S. energy policy, by accounting for limited powers, uncertain autonomy, cooperation and conflict, interstate differences, and intersecting policies. Additionally, the authors identify implications of overlapping authority for policymakers, regulators, and industry leaders, including polycentric policymaking venues, direct and indirect policy effects, and energy system governance. Overlapping authority provides a framework for understanding intersecting roles of national, state, and local governments in energy policy.