LAUSR

Veto player theory is a powerful approach to comparative politics. This article argues that the debate about its explanatory success would benefit from more systematic distinctions. The theory not only comes in different theoretical variants, it is also used in radically different ways empirically. Starting from recent debates about the ‘testing’ of theoretical models, the article distinguishes five ways in which theoretical models can be used empirically: contrastive, axiomatic, exploratory, presumptive and modular. The typology is applied to veto player theory and illustrated with exemplary studies and debates. The article concludes that each type raises different questions that should be answered in individual studies. Moreover, while veto player theory has an excellent track record on four empirical uses, the picture on its contrastive use is far more nuanced. More explicitly contrastive testing of the theory is desirable.