The Supreme Court unanimously agreed yesterday to reject a lawsuit brought on by six states, New York City, and several land trusts, seeking to reduce carbon dioxide emissions from major power plants. Justice Ruth Bader Ginsburg said that under the Clean Air Act, the case must be addressed by the Environmental Protection Agency, rather than by the courts. The Supreme Court maintains their 2007 ruling that only the EPA can dictate regulations on greenhouse gas emissions, but meanwhile Congress is trying to strip the EPA of its very ability to regulate these emissions. Joining us with more on the case is Robert Hernan, author of "This Borrowed Earth: Lessons from the Fifteen Worst Environmental Disasters Around the World," and former Assistant Attorney General in the Environmental Protection Bureau of the state of New York. Also with us is Jeff Rosen, professor of law at George Washington University and the author of "Supreme Court: The Personalities and Rivalries that Defined America." Rosen will discuss this case and another notable Supreme Court ruling from this week, from the landmark class action suit against Wal-Mart.