Which Way to U.S. Climate Cooperation? Issue Linkage versus a U.S.-based Agreement Jon Hovi 2 , 1 and Tora Skodvin 3 , 2 1 Department of Political Science University of Oslo P.O. Box 1097 Blindern 0317 Oslo, Norway e-mail: jon.hovi@stv.uio.no 2 CICERO – Center for Climate and Environmental Research Oslo P.O. Box 1129 0318 Oslo, Norway e-mail: tora.skodvin@cicero.uio.no 3 Corresponding author Word count (including front page, abstract, endnotes and references): 10.445 Acknowledgement: We are indebted to two anonymous reviewers for helpful comments, to Frank Azevedo and Lynn Nygaard for excellent editorial assistance, and to the Research Council of Norway for financial support.