Sincere cooperation and European integration: a study of the pluriformity of loyalty in EU law.

The principle of sincere cooperation (also called loyalty or loyal cooperation), laid down in Article 4(3) of the Treaty on European Union, requires that EU Member States facilitate the Union’s tasks, adopt all necessary measures to fulfil their obligations under the Treaties and refrain from any actions that could jeopardize the realization of EU objectives. In the case law of the Court of Justice of the European Union, this general duty has spawned a large number of more specific yet unwritten obligations for Member States.

Those unwritten loyalty obligations have had a far-reaching impact on national autonomy. They restrict Member States’ freedom to act, and sometimes severely so, despite the fact that they have retained the competence to act according to the Treaties. The strictures of loyalty moreover do not vary depending on the nature of EU competence.

As such, the Court’s loyalty jurisprudence presents a challenge to fundamental principles underpinning Union law. Most obviously, it appears to contradict the notion that the Union only has those competences that the Member States have conferred upon it (conferral). On a more fundamental level, the Court’s loyalty jurisprudence seems to undercut some of the basic qualities of a legal system that adheres to the rule of law. Since it appears to leave significant room for judicial discretion, can it still be said that the law itself governs and, if so, is the law foreseeable enough?

This study asks whether loyalty can be reconciled with these principles and, therefore, where its limits lie. Existing scholarship has had a hard time conceiving of such limits, in large part because it viewed the principle of sincere cooperation as virtually unique. Loyalty is typically described as characteristic of the EU legal order, which in turn is seen as a ‘one of a kind’ (sui generis) legal system that can be explained neither as a product of international law (i.e. as an international organization) nor as an application of constitutional law (i.e. as a federal state).

This study advances another theory. Based on comparative research into international law and German constitutional law, it is argued that loyalty is an application of the principle that all treaty obligations must be fulfilled in good faith, a principle which is common to both international and constitutional law. Good faith, in turn, must be understood as a principle of constructive interpretation, which demands that a legal practice is interpreted in a way that best justifies that practice. This explains why the strictures of good faith vary with the normative context. In line with this argumentation, it is submitted that both the text of Article 4(3) TEU and other general principles of Union law frame the Court’s discretion in applying loyalty.

The dissertation applies this theory of loyalty as good faith to American federalism, which historically has rejected a similar duty to cooperate, and to the area of EU external relations, where loyalty has imposed particularly stringent duties of cooperation. Examining the EU and US constitutional system through the prism of cooperation lays bare the deep structure and political morality of both types of federalism.