Intraparty Politics and Electoral Competition 1 Micael Castanheira 2 Benoit S Y Crutzen 3 Nicolas Sahuguet 4 December 15, 2006 1 We thank Estelle Cantillon, Mathias Dewatripont, Jean Hindriks, Georg Kirchsteiger, Patrick Legros, Abdul Noury, Gérard Roland, Jim Snyder, Yossi Spiegel, Otto Swank, and Guido Tabellini for insightful discussions. We also thank participants at the EPCS conference, at the Workshop on Political Economy in Brussels, at JMA, ESSET, ESEM, as well as seminar participants in ECARES, Mannheim, UQAM, and Rotterdam for useful comments. 2 ECARES and CEPR, 50 Av. Fr. Roosevelt, CP114 1050 - Brussels Belgium. Tel: +32-2- 650.44.67. Email: mcasta@ulb.ac.be. Micael Castanheira is FNRS research fellow and gratefully acknowledges their financial support. 3 Erasmus Universiteit Rotterdam, Department of Economics - H8-11, Postbus 1738, 3000 DR Rotterdam, The Netherlands. Tel: +31-10-408.13.91 Fax: +31-10-408.91.61 Email: crutzen@few.eur.nl 4 IEA, HEC Montréal, CIRPEE and CEPR, 3000, chemin de la Côte-Sainte-Catherine, Mon- tréal (Québec), Canada H3T 2A7; Tel: (514) 340-6031; Fax: (514) 340-6464; email: nico- las.sahuguet@hec.ca