Will Nations ever come together to keep climate out of the severe danger zone? The question looms like a cloud over United Nations negotiations in Paris this month—the 21st such attempt to forge an international agreement to curb greenhouse gas emissions. A big reason for failing to find common ground is American intransigence on the role of government. If nations are to succeed, the U.S. will have to give up on the idea that free markets alone can adequately address climate change and embrace a government-led plan of action.