A central feature of the international legal system is that States are the predominant actors within the system and possess international legal personality. As a result, States are able to enter into legal relations with each other by way of treaties, possess certain international legal rights as bestowed under international law, and are capable of enforcing those legal rights in international litigation or of being the subject of a claim if they are derelict in meeting their international legal obligations. This raises two important issues. First, how are ‘States’ characterised and recognised under international law? Second, are States the only international actors that possess international legal personality?
A number of factors have increased the significance of this area of international law. To begin, States, and the notion of ‘statehood’, have undergone significant evolution in recent centuries, and contemporary international law has had to keep abreast of these developments. While international law recognises that there are essential attributes to what comprises a ‘State’ for the purposes of the international legal system, there remain important political processes at play with respect to the recognition of States. During the United Nations (UN) era this question has assumed particular importance due to a number of factors. The first is that since 1945 the international community has witnessed an unparalleled growth in the number of States. This is simply evidenced by the growth in the membership of the UN, which has expanded from the original 51 members in 1945 to 193 members in 2017. This growth in the number of States within the international system can be attributed to a number of factors, of which the process of decolonisation has been one of the most significant. Another contributing factor in the past 30 years has been the break-up of former federated States such as Yugoslavia, and the emergence of new republics in Eastern Europe following the end of the Cold War. Consequently, the law that governs the emergence and recognition of new States, including their membership of international organisations such as the UN or NATO (North Atlantic Treaty Organization), has since 2000 attained particular contemporary significance.
The second factor that has made this area of the law relevant during the UN era has been the emergence of an ever increasing number of international organisations that claim to possess international personality.