When 10 of the largest U.S. corporations and four environmental groups joined forces last January to lobby for federal regulations to restrict greenhouse-gas emissions, it was seen as a watershed in corporate environmentalism.

The U.S. Climate Action Partnership (USCAP), comprising 27 companies from General Electric to General Motors, won praise from enviros by endorsing cuts — 10% to 30% of heat-trapping emissions within 15 years and 60% to 80% by 2050 – to avert some of the severest consequences of global warming. Behind the scenes, however, several companies that belong to USCAP are simultaneously supporting efforts and organizations that oppose mandatory cuts in greenhouse gases or promote policies that would make the USCAP reductions nearly impossible to meet.