What powers do to several states of the United States have individually to enter into environmental agreements with other sovereign nations? In this article, the author reviews the power that states may have generally and then specifically regarding environmental agreements. Several traditional tools of analysis have historically been used including the constitutional doctrine of pre-emption, cooperative federalism and the foreign affairs doctrine. Some newer tools of analysis are also offered including the revival of the treaty-compact and the author's own concept of "de-emption". The United States Senate's explicit refusal to ratify the Kyoto Protocol, coupled with the consequent state initiatives to control greenhouse gasses - especially the documents concluded between New Jersey and the Netherlands, provide rich examples of these tools in contemporary action
