Introduction

Classic international law holds that each State can choose the relationship between its “domestic” law and “international” law. Two – constitutional – theories thereby exist: monism and dualism. Monist States make international law part of their domestic legal order. International law will directly apply as if it were domestic law. By contrast, dualist States consider international law separate from domestic law. International law is viewed as the law between States; national law is the law within a State. While international treaties are thus binding “on” States, they cannot be binding “in” States. International law here needs to be “transposed” or “incorporated” into domestic law and will thus only have indirect effects through the medium of national law. The dualist theory is based on a basic division of labour: international institutions apply international law, while national institutions apply national law.

Did European law leave the choice between monism and dualism to its Member States? Section 1 examines this question in greater detail, before the remainder of this Chapter explores the doctrine of direct effect for European law. Section 2 starts out with the direct effect of the European Treaties. The European Court indeed confirmed that some Treaty provisions would be self-executing in the national legal orders. Nonetheless, the European Treaties are framework treaties; that is: they primarily envisage the adoption of European secondary law. This secondary law may take various forms. These forms are set out in Article 288 TFEU.