This paper evaluates how the power of federal courts in a system of dual federalism affects state-level representation. I develop a framework in which federal courts establish a "federal floor" in a given policy area, thus creating an asymmetry---states in which the legislature has chosen a lower level are compelled to shift policy to the floor, whereas states in which legislatures or voters prefer levels above the floor are unaffected. I develop versions of the framework in which the status quo at the state level may lag behind changes in public opinion, and in which cross-state moral externalities exist. In doing so, I use the framework to recast the familiar "counter-majoritarian difficulty'"--the problem of unelected judges striking down legislation enacted by elected legislatures--as an issue of federalism. To illustrate the framework, I present a quantitative analysis of the path to the legalization of same-sex marriage in all 50 states, using both original and existing data on public opinion, federal and state judicial decisions, and state-level policy.