The American Clean Energy and Security Act of 2009 (ACES), also known as the Waxman-Markey Bill, was a comprehensive cap-and-trade bill passed by the House of Representatives on June 26, 2009, by a vote of 219-212. Sponsored by Representatives Henry Waxman (D-CA) and Ed Markey (D-MA), it aimed to address climate change through emissions reductions by establishing a cap-and-trade system for greenhouse gases similar to the European Union Emission Trading Scheme. The legislation included five main titles covering clean energy development, energy efficiency standards, reductions in specified greenhouse gases and hydrofluorocarbons, transitioning to a clean energy economy, and agriculture/forestry offsets. Despite House approval, the bill faced significant opposition and was never brought to the Senate floor for a vote, marking the first time the House approved such comprehensive climate legislation while highlighting partisan divides on climate policy. Although it did not become law, its passage in the House was a milestone in U.S. climate policy that influenced subsequent discussions on energy independence and emissions reductions.