Will nations ever come together to keep climate out of the severe danger zone? The question looms like a cloud now that President Donald Trump has announced that the U.S. will withdraw from the Paris climate change accords—an international agreement to curb greenhouse gas emissions. But the nation’s ambivalence about climate change long predates the last presidential election. A major reason is American conservatives’ hostility to government intervention. If the U.S. and the world are to succeed in limiting disruptive climate change, the U.S. will have to give up the idea that free markets alone can adequately address climate change and embrace the reality that markets need help from governments.