The document discusses the emergence of the principle of supremacy of EU law over national laws of member states. It analyzes key court cases that helped establish this principle, including Van Gend en Loos, Costa v Enel, and Simmenthal. These cases found that EU treaty provisions can create direct rights for individuals, that EU law forms an autonomous legal system, and that national courts must apply EU law even if it conflicts with national law. However, some tensions have arisen from EU law supremacy limiting member state sovereignty and control over their own laws.