Panelists talked about enforcement of federal regulations by the Environmental Protection Agency, global warming, and the Supreme Court case Massachusetts v. Environmental Protection Agency, on which oral arguments were heard earlier in the day. Several states and environmental organizations had argued that the EPA must regulate the amount of carbon dioxide that comes from car emissions -- greenhouse gases that are said to cause global warming -- under the Clean Air Act’s provisions requiring it to regulate any air pollutant that “endangers public health or welfare.” The EPA claimed that they did not have authority to regulate air pollutants associated with climate change. The panelists discussed the oral argument, the merits of the case and the potential effects depending on how the Supreme Court rules. Following their presentations they answered questions from members of the audience.