Very soon, President Obama’s EPA will propose the administration’s most significant effort to tackle the climate crisis. The new rule will curtail greenhouse gas pollution from existing power plants—the nation’s largest source of carbon emissions. Environmentalists, industry groups, and state governments have been vocal regarding their preferences for the shape of the regulation. In this policy brief, Jack Lienke and Jason Schwartz survey 30 public letters, white papers, presentations, and reports from these stakeholders and outline their positions.