Criticism of the Bush administration's environmental policy is increasing, with opponents pointing to loose regulation as a major issue. Both Republican John McCain and Democrat Barack Obama have taken environmental stances that differ from the current administration. While the environment is important to U.S. voters, the economy and jobs remain their top concerns. Opponents both inside and outside of government have criticized the White House for its stance on a variety of environmental issues, such as carbon emissions, endangered species protection, and pollution cleanup. Senator Barbara Boxer and Frank O'Donnell have both spoken out against the Bush administration's perceived efforts to weaken environmental regulations for the benefit of special interests, arguing that this approach comes at a significant cost to public health and well-being. A Capitol Hill staffer familiar with global warming legislation accused the Bush administration of actively working against efforts to reduce greenhouse gas emissions that contribute to climate change. The staffer claimed the administration obstructed progress and did everything in its power to prevent any action from being taken. In response, James Connaughton, the head of the White House Council on Environmental Quality, argued that the Bush administration has actually achieved equal or greater environmental successes compared to previous administrations, sometimes through regulation and sometimes through incentives. Connaughton criticized states, particularly California, for setting ambitious environmental standards but not meeting them. He criticized Congress for not reinstating the Clean Air Interstate Rule, which aimed to reduce power plant pollution, after it was rejected by a federal appeals court in July. Despite promising to regulate carbon emissions during his presidential campaign in 2000, Bush changed his stance once in office, citing potential job losses and unfair advantages to countries like China and India. The Supreme Court ruled in 2007 that the EPA had the authority to regulate greenhouse gases if they posed health risks. The EPA postponed a decision on this finding, leaving the task of regulatory action to either Obama or McCain after the election. The Bush administration's track record on protecting endangered species has faced criticism from conservation groups. To date, the current president has only listed 58 species under the Endangered Species Act, a stark contrast to the 522 listed under President Bill Clinton and 231 listed under President George H.W. Bush. The Bush administration waited until the last minute to list the polar bear as threatened by climate change, with Interior Secretary Dirk Kempthorne stating that the listing would not directly address climate change and that he was implementing measures to prevent the decision from being exploited for global warming policy. The decision was commended by the U.S. Chamber of Commerce as a sensible compromise between business interests and environmental considerations. During a hearing of the Senate Environment and Public Works Committee on September 24, Boxer criticized the Bush administration for allegedly attempting to weaken the EPA and Interior Department's efforts to safeguard public health and the environment.