Progressivism in the nineteenth century gave birth to both international law and Marxian thought. Despite Marx's low interest in international law, several elements of his writings are quite important. Where (modern) international law grew secular and centred on nations and human rights, (early) Marxian thought would argue that it had not gone farther in its secularisation. Statehood and individual rights, on the other hand, appear to be types of political theology. Deconstruction takes on part of Marxian dialectics’ legacy today. In this paper the author has tried to find the pieces available for the Marxian approach to the sources of international law and interpretation of international law as a whole.