There is, after years of debate, a widespread though not universal consensus in the United States that climate change is real, that it is primarily the result of human activity, and that it poses a serious global threat. A consensus on the appropriate U.S. response, however, remains elusive. While the new focus on climate change suggests that the United States may play a key role in attempts to negotiate a new international agreement to reduce global emissions,2 there is serious debate in academic and policy circles over whether doing so would be in the national interest. Indeed, some argue that a straightforward cost-benefit analysis weighs against U.S. action.