On June 1st, 2017, the United States, the second largest greenhouse gas emitter in the world, announced its withdrawal from the Paris Agreement on climate change. The global deal to reduce global emissions of greenhouse gases was ratified last year by almost 200 countries. Although the decision had been previously announced in Donald Trump’s campaign, his decision to follow through on his word came as a shock to the international community. Why did the US leave such a major framework for cooperation? What are the international effects of the US withdrawal? Will this decision propel American leadership? Or will it bury it?