Research on the enlargement conditionality of the European Union sustains opposite positions on thequestion of whether it represents a means of coercion or an invitation to voluntary adaptation.However, it reveals no dialogue between advocates of these opposed views. In an attempt to replacethis gap in communication with a research agenda, this article undertakes a theoretical investigation ofthe main arguments for regarding compliance with conditionality either as an effect of coercion or as avoluntary choice. It is found that both of these views are worth taking seriously but also that they arepremature and in need of further theoretical and in particular empirical clarification. It is suggested,moreover, that coercion and voluntary adaptation are best viewed as complementary rather thancompeting descriptions of complying with conditionality.