In the United States to date, most of the first genuine steps toward addressing the challenge of climate change have taken place at the state level. Many states have proceeded in a meaningful, comprehensive fashion while the federal government struggles to take its first significant step toward legislative or regulatory action. Yet it is clear that these state actions, even when taken together, are not enough to put the United States on a course to reduce greenhouse gas emissions to the level deemed necessary by the science. This paper aims to further a constructive dialogue on the appropriate roles for state and federal government in meeting the challenge of climate change in the United States.