Iraq’s Divided Majority: Democratisation, Consociationalism, and In-Group Rivalry challenges conventional accounts of consociational democracy by examining how power-sharing arrangements can intensify political competition within, rather than between, groups. Shifting the focus from inter-group accommodation to intra-group rivalry, the book argues that consociational systems often compress diverse constituencies into artificially homogeneous blocs, distorting representation and generating instability from within. Adopting a constructivist understanding of identity, it explores how political actors mobilise and contest sectarian identity in post-2003 Iraq. Focusing on intra-Shia rivalry - the most consequential arena of political competition in the Iraqi system - the study traces developments from 2003 to 2022 across four key themes: electoral politics and government formation, the role of the Marja?iyah, Iranian influence, and the Tishreen protest movement. Drawing on Critical Discourse Analysis of elite speeches alongside in-depth interviews, it demonstrates how Iraq’s Muhasasa system falters not simply because of poor performance, but because it assumes cohesion where fragmentation persists. This book will appeal to scholars and students of Middle East politics, comparative politics, and democratic theory, as well as policymakers and analysts interested in power-sharing, identity politics, and institutional reform in divided societies.