For at least a decade, states have exercised de facto national leadership on climate change policy development. Through comprehensive planning, intensive fact-finding, and stakeholder-based consensus-building, they have developed and refined a broad range of laws and policies intended to advance climate, energy, and economic policy objectives simultaneously. The recommended portfolios of actions derived from this work, involving more than one-half of all U.S. states and regions, as well as the formal participation of more than 1, stakeholders and technical experts, show the potential of appropriately crafted measures to expand the economy and create jobs, reduce energy conflicts and improve energy security, build businesses and stimulate new investment, foster new technologies and management practices, protect households and businesses from high and fluctuating energy prices, and reduce emissions of greenhouse gases (GHGs) and other pollutants.

At the federal level, the United States is in the midst of a congressional debate about how to craft a national climate change program. Depending on its final resolution, this program could either displace or enhance state leadership and stakeholder consensus. Proposed federal cap-and-trade legislation, combined with other national measures, could substantially reduce GHG emissions by 2050. The U.S. House of Representatives narrowly passed a bill based on this policy architecture, the American Clean Energy and Security Act, in 2009 without Republican support. Several months later, the U.S. Senate Environment and Public Works Committee approved a similar bill along partisan lines. In May, Sens. John Kerry (D-Mass.) and Joseph I. Lieberman (I-Conn.) made public the discussion draft of a bill (that was prepared with Sen. Lindsey O. Graham (R-S.C.)) that significantly departs from previous legislation approved in the House and the Senate Environment and Public Works Committee. Moreover, Sen. Jeff Bingaman (D-N.M.) introduced comprehensive energy legislation without a cap-and-trade system.