Dropping the unitary actor assumption: The impact of intra-party delegation on coalition governance

Abstract

What happens to cabinet governance if parties do not act as ‘unitary actors’? In this paper, I examine the consequences of intra-party dissent for coalition governments in parliamentary systems. Drawing on the principal–agent literature, I develop a model in which party agents, namely cabinet ministers and legislators rather than parties as collective actors, decide on specific policies. The individuals’ amount of loyalty determines the degree of party unity. I use simulation techniques to analyze the power of an agenda-setting minister in a two-party coalition conditional on the level of party unity. The results suggest that the minister’s agenda-setting power diminishes if parliamentarians and cabinet members aim at implementing their personal policy preferences. However, the party not in charge of the respective portfolio may benefit from disunity within its own ranks. This counter-intuitive result raises doubts about the widespread view that internal unity strengthens the bargaining power of political parties.