 Welcome back. In this first lesson we'll try to understand why law-making is a different problem in international law compared to what it is in domestic law. In domestic law the question of the sources is a fairly easy and straightforward problem. If you want to know what can't as law in any municipal legal system, you usually turn to the constitution of the state and most often than not will it list the various types of legal sources together with the procedures that must be followed to enact any of them. Furthermore, the constitution will identify the various powers and the authorities within the state and allocate to each of them the specific sources and law-making processes. And the resulting picture is one of a pyramid with the constitution standing at the top as the Grundnorm in the theory of Hans Kelsen. And as a result there is a clear typology of domestic sources and also a clear hierarchy between the various domestic sources of the law. Not only must each domestic law decree or decision be enacted in conformity with the procedures described by the constitution, but there must also be a substantial conformity of each domestic source with the source standing above it in the legal pyramid. The validity of each legal act is defined by its place in the pyramid, its relation with the other sources and other higher rules contained in the pyramid. As we have seen from the first weeks of this course things are pretty different in international law where the main subjects and creators of the law are states and states are said to be equal and sovereign which means that each of them has the same legal capacity and none of them stands above any other. Of course some are more powerful and more influential but no state has by law any legal authority or superiority over any other. One state cannot make law on behalf of another state and for that other state. The basic structure of international law resulting from the equal sovereignty of states is an horizontal structure has opposite to the idea of a pyramid. International law is flat, not hierarchical. In such a situation the law cannot be created as a result of the will of a higher authority because there is no such higher authority, all states being equally sovereign in law. Therefore law will have to result from some form of consent of the states concerned. If law cannot be wanted and opposed by one authority over the subjects, it is then up to the subjects to give law to themselves by creating law by themselves but this raises two fundamental questions. First, how is it compatible with the notion of sovereignty? How is it possible to reconcile the notion of sovereignty with the notion of law to court? If sovereignty means autonomy, the absence of any higher authority, how is it possible in any way to limit sovereignty by law? And the second question is as follows. When it wants to do something, must a state find in a binding rule of international law the justification and the limit for its action, how is it free to act as it pleases absent any rule prohibiting what it intends to do? To phrase the question in more theoretical terms, do states derive their powers and competences from international law? Or is it that because states are sovereign by nature as it were, that they are just free to do as they want as long as they do not breach any rule of international law that they are bound to respect? Is international law a prohibitive or permissive legal order? Those two questions have been answered by the Permanent Court of International Justice which is, as you may recall from the second week, the court established under the auspices of the League of Nations in the 1920s and from which the International Court of Justice took over when the United Nations was founded in 1945. In the following lesson, by reading from the Wimbledon and from the Lotus cases, we will see what are the answers of the Permanent Court of International Justice to those two questions.