As federal climate legislation stalls, U.S. states and regional alliances are forging their own carbon pricing pathways. From California’s cap-and-trade to the Regional Greenhouse Gas Initiative, these regimes are advancing domestic emission reductions and also influencing global market designs. With prospects for integrating with emerging international schemes, like the EU’s Carbon Border Adjustment Mechanism, there is continued opportunity for subnational actors to exhibit climate leadership. This discussion explores how subnational governance can drive credible carbon pricing, strengthen global coalitions, and send powerful market signals beyond national borders.