--- - |2+ Objective We investigate whether state‐level policy adoption of environmental regulations leads to nationalization of similar policies and, if so, the mechanisms by which members of Congress are incentivized to vote strategically. Method We examine several key environmental policies (i.e., renewable portfolio standards and regional cap‐and‐trade agreements) and utilize historical state‐level inventories and congressional roll‐call votes in our analysis. Results We demonstrate that Democratic and Republican members of the U.S. House in both scenarios were much more likely—even after controlling for ideology and constituency preferences—to vote in favor of increasing environmental regulations if their home state already put such a policy in place. Conclusion In a new political era where federalism within environmental policy is being reimagined, the lessons learned from the Waxman‐Markey cap and trade bill and the Udall RPS Amendment teach us of the importance of state‐level initiatives serving as powerful drivers for increasing pressure for federal adoption. - 'Social Science Quarterly, EarlyView. '