As in other countries, public authorities in the US have initiated an array of experiments collectively designed to mitigate the threat posed by global warming. This paper considers the implementation of global climate protection in the Seattle metropolitan region of Washington State. Specifically, the discussion focuses on regulatory, institutional and investment changes within the handful of municipalities formally pledged to address carbon goals as articulated by their statutory participation in the US Mayors' Climate Protection Agreement. While enrollment in such networked spaces has created crucial momentum for practical policy action, the hardest work is just starting: namely, transforming the physical, institutional, economic and cultural constitution of actually existing political communities. Interrogating new data gleaned from recent research on local 'cool city' developments, the discussion assesses overall progress within the context of broader debates in the extant literature on local planning and policy for global climate action.