1 Drivers of Collaboration in Political Decision-Making: A Cross-Sector Perspective Manuel Fischer, Department of Environmental Social Sciences, Eawag, Überlandstrasse 133, 8600 Dübendorf, Switzerland. Email: manuel.fischer@eawag.ch. Pascal Sciarini, Department of Political Science and International Relations, University of Geneva, Boulevard du Pont d'Arve 40, 1211 Geneva 4, Switzerland. Email: pascal.sciarini@unige.ch. --- Accepted for publication at the Journal of Politics ---