ABSTRACT
Member State courts; (ii) prevention of enactment of conflicting legislating by Member
State governments.
5. However, the Treaties themselves make no reference to supremacy over all national law. The closest is the former Art 10 (the duty of loyalty) (now in Art 4(3) TEU): ‘Member States shall take all appropriate measures … to ensure fulfillment of the obligations arising out of this Treaty or resulting from actions taken by the institutions … They shall abstain from any measure which could jeopardize the attainment of the objectives of the Treaty …’. This has become a major tool in the hands of the ECJ.
