Broadly speaking, there are three approaches to international collective action issues: those of legal scholars, economists, and international relations experts. Each offers a particular view on the problems it faces and on the nature of the solutions.

For the jurists, it is all about the force of law. As the great legal theorist Hans Kelsen wrote as early as 1934, “All law is, by its very nature, an order of constraint […] If international law is a true law, a law in the same sense as domestic law, it must necessarily include an order of constraint; it must be able to compel the states subject to it to adopt a definite attitude, by establishing the sanction which must be imposed on a state which does not adopt the prescribed attitude”. Kelsen did not hide his contempt for the League of Nations, which failed to establish such an international order, and in retrospect it is hard to disagree.

What Kelsen (1934) is aiming for is nothing less than a global rule of law based on principles that are sufficiently universal to be incontestable (see Stern 1936). The issue, he says, is not moral or political. It is a question of establishing the appropriate means to achieve a goal that is beyond discussion. This problem must be addressed by the technique of international law, which he places at the top of the hierarchy of legal norms.

Reality will never strictly conform to the architecture envisioned by Kelsen. But in its purity, the global rule of law designates an ideal to which many would refer in the 1940s when the question arose à propos the building of the international system of the postwar period. Among others, the International Monetary Fund (negotiated in 1944 at Bretton Woods), the International Trade Organization (negotiated in 1948 but never ratified), the International Criminal Court (established in 1998, but far from universal) bear this mark. The same is true of the European Union, whose law is superior to national law. In this spirit, a lawyer will always begin by examining the texts to determine whether states are subject to real obligations, and whether the institution in charge of a given area has the capacity to sanction breaches of these obligations.