On February 5, 2009, she led an 18-state coalition, as well as the Corporation Counsel for the City of New York and the City Solicitor of Baltimore, urging the Environmental Protection Agency to take action in response to the 2007 U.S. Supreme Court ruling in Massachusetts v. EPA. Though the Supreme Court ruled that the EPA did have the authority to regulate greenhouse gases under the Clean Air Act, the Agency had yet to make an official decision on whether it believes that greenhouse gas emissions pose dangers to public health or welfare.