For several years the battle to reduce emissions of greenhouse gases has focused on the automobile. Hummers became public enemies and the Prius was suddenly chic. Now, Washington has found a new villain in the fight against global warming—American homes. John Dingell of Michigan and other key members of Congress are considering painful measures, including eliminating the cherished mortgage deduction for wasteful McMansions. It's a sign that the global warming fight is now more about ways and means than science. Is it a political ploy or are McMansions going to go the way of the gas guzzler? Jim Sterngold guest hosts.