The politics of fission: an analysis of Faction Breakaways among Italian Parties (1946–2011)

This article investigates intra-party politics and explores the determinants of factional breakaways, going beyond the unitary actor assumption. It presents a game-theoretic model that focuses on intra-party competition and bargaining dynamics to analyse the interplay between party leaders and minority factions. It tests several hypotheses based on the formal model using a new dataset that contains information about the strength and policy positions of factions inside Italian parties, from 1946 to 2011, measured through quantitative content analysis of motions presented during party congresses. The results show that office, policy and electoral motives influence factions' decisions to break away. Other elements - such as intra-party democracy, the electoral system and party system competitiveness - also affect leaders' attitudes toward compromising and alter the likelihood of a split.