Defection in the European Union. An Explanation for EU Treaty Opt-Outs

Abstract: This paper develops a theoretical approach towards understanding treaty opt-outs from EU common policies by drawing on Putnam’s Two-Level Games theory. In doing so, the paper first presents treaty opt-outs as defections from negotiations by looking at previous research regarding opt-outs. Then, the paper goes on to concentrate on different European integration theories in order to explain their shortcomings in explaining defection from negotiations. Drawing from this discussion, the thesis presents Putnam’s two-level games approach as the theoretical basis chosen in order to study opt-outs as defections from negotiations. Focusing on Putnam’s theoretical insights regarding defection, a theoretical framework based on three analytical dimensions is built in order to explain opt-outs. Finally, four cases of opt-outs from EU common policies are analysed empirically, by comparing them along the three analytical dimensions. The purpose of this comparative analysis is to assess whether there are any patterns of similarities that might account for the defection that occurred in all of the opt-out cases examined. The results from this analysis indicate that the main factors triggering defection are the ones imposed by the domestic constraints. Following the comparative analysis of the four opt-outs along the three analytical dimensions, a further explanation of defection is explored. Thus, based on the findings, the final part frames a theory about opt-outs by revisiting Putnam’s assumptions. The developed theory builds on Putnam’s concept of “win-set” and argues that domestic constraints represent the key explanatory factor triggering defection and thus, the formulation of treaty opt-outs.