Introduction
Debates on the causes of coalition (in)stability date back to more than a century ago; coalition governments have at times been referred to as “structurally weak and unstable” (Lowell, 1896), whereas others (Lijphart, 1994; Rokkan, 1970; Sartori, 1976) have repeatedly emphasised that “multi-party coalition systems are not necessarily unstable and ineffective”. Coalition-building has been seen as coming out of bargaining and compromise between political parties, often as a strategy to achieve electoral success. Research on the relationship between political parties and coalition- building has mainly privileged coalition-building among parties and government formation, rather than exploring how the parties’ internal dynamics influence the stability of the coalition itself, and how this affects policy performance.