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 is withdrawing the U.S. from the Paris climate change accord—an international agreement to curb greenhouse gas emissions. But the nation’s ambivalence about climate change long predates the last presidential elect—on. A major reason is some American conservatives’ hostility to government intervention. If the U.S. and the world are to succeed in limiting dis ruptive climate change, the U.S. will have to give up the idea that free markets alone can adequately address climate change and accept the reality that markets need help from governments.