Why do the EU member states accept the supremacy if European law? Explaining supremacy as an alternative to bilateral reciprocity

Abstract:

The work of Burley and Mattli, Alter, and Stone Sweet, taken together, provides the dominant political science explanation for the supremacy of European law. This review identifies a range of empirical and theoretical difficulties with this explanation, including the lack of a specified alternative outcome, an overemphasis on national constitutional rights, a limited understanding of the possible relationships between national law and 'ordinary' treaty obligations, ambiguity on the essential question of whether national political institutions could unilaterally legislate contrary to European law, and the failure to provide an explanation for state behaviour compatible with European law supremacy.

The paper then sets out a research agenda, emphasizing the need to identify independent variables which could produce, depending on their values, outcomes like the EU which rely on states accepting the supremacy of treaty obligations or, alternatively, tit-for-tat regimes like the World Trade Organization which rely on bilateral reciprocity enforcement mechanisms.