Explaining the formation of minimal coalitions: Anti-system parties and anti-pact rules

Abstract.  Recent theoretical arguments hold that the institutional setting of a political system influences coalition formation. Empirical analyses that confront these hypotheses have, however, been slow to emerge. We provide a first test of the relation between coalition formation and one element within this institutional setting: the existence of commitments not to join forces with certain 'pariah' parties (i.e., anti-pact rules). Specifically, we study the effect of the 'cordon sanitaire' around the Flemish extreme right-wing party Vlaams Blok over the period from 1976 to 2000. The results show that the refusal to coalesce with Vlaams Blok significantly affects the probability that 'minimal winning', 'minimal number' and 'minimal size' coalitions are formed.