By: John Boonstra on June 12, 2009 Guest posting at Opinio Juris, climate expert Nigel Purvis answers a very tricky question — indeed, what may prove to be the trickiest — about U.S. efforts to slow climate change. Here’s the problem in a nutshell: U.S. domestic legislation must contribute to a genuine global solution but global arrangements must also fit or alter domestic political realities. Every country, in fact, is going to have to align what is practically achievable in their domestic political systems to what is needed to stop global warming. It’s just particularly tough in the United States, both because segments of our political system are so vehemently opposed to action on climate change and because our impact on the global environment has dwarfed that of any other country. Purvis’ solution? It gets wonky, but the point is to synch up U.S. domestic and international legislation. Both are going to be tinkered, and the ultimate effectiveness of both will depend on future commitments and the rest of the world meeting its end of the bargain. An all-encompassing treaty, therefore — which would also require a 2/3 vote in the Senate, rather than a simple majority in both houses — would be more difficult to pass, less likely to match U.S. legislation, and possibly less effective. It’s unrealistic to think Congress has the time and attention to take up domestic legislation and an international agreement separately (in whatever order). It is even more unrealistic to assume that an international treaty would be consistent with U.S. legislation and congressional wishes unless Congress has created in advance a process that helps ensure this alignment. In twenty years of climate diplomacy neither Congress nor the Senate has given the President of the World a clear blueprint for U.S. global leadership on climate change…America needs a well-defined plan for climate cooperation and that plan should have the force of law. I encourage you to read the whole post.