We only partially understand the rise of subnational North American governments as carbon-pricing pioneers because fewer than half of the jurisdictions that consider a carbon-pricing policy (CPP) implement one. This article contributes to the literature on CPPs that relies on political economy dynamics and power relations to explain not only policy outcomes but also the lack thereof. Using a qualitative comparative analysis of fifty-four cases, the article shows that subnational governments that have officially considered a CPP tend to implement it if the visible and local co-benefits of mitigation help them bear the political and economic costs of pricing emissions. Findings also show that the regulation of industries with high risk of carbon leakage does not automatically preclude the enactment of CPPs and that the scope of the policy may be more decisive for implementation.