For 2 years industry officials, states, and environmentalists have had 2 January 2011 circled on their calendars. That’s the date greenhouse gases officially become regulated pollutants under the Clean Air Act—a direct result of a 2007 ruling by the U.S. Supreme Court that carbon dioxide is a pollutant under that law. The Environmental Protection Agency’s effort to control greenhouse emissions will only get more controversial as myriad lawsuits challenge the regime and Republicans, now ascendant in the House of Representatives, seek to stop EPA in its tracks.