Supremacy, the Uniformity of EU Law, and the Principle of Equality

Despite being one of the pivotal principles of European Union law, there still is no consensus on the rationale for the supremacy of the law of the European Union over the law of the Member States. There is also not much discussion on the repeated claims in case law that Union law must have uniform application in the Member States. This paper suggests that both supremacy and uniformity can be understood as preventing the discrimination of indi-viduals that would be caused by the divergent application of Union law in the Member States. In this respect, Member state-centred non-discrimination, now provided in Article 4(2) TEU on the equality of Member States, (merely) complements individual-centred non-discrimina-tion, anchored in Article 18 TFEU and Article 21 CFR. Moreover, this paper discusses how these two standards relate to what is referred to as the unity of the internal market.