We started off our International Relations course by brushing up on the history of modern Europe – beginning with the 14th century. The feudal structures which had survived for centuries slowly crumbled as kings centralized power in their hands at the expense of the dukes, counts and barons. Slowly, the concept of a unified territorial state emerged and its sovereignty was firmly established at the Treaty of Westphalia in 1648. The concept of sovereignty is especially important because previously, the Church could interfere in the domestic affairs of states. However, from 1648, the State had sole authority within its territory, and no other power could interfere in its domestic arena. This created a system where all states were recognized to be legal equals, bringing order into a chaotic scenario. Thus was the inter-state system born.
Such a model of an inter-state system was not the only one to emerge. The Chinese and Islamic civilizations had their own unique and alternative systems that regulated inter-state relations. However, because of colonialism, imperialism and the spread of European thought all over the world, the European model has been adopted all over the world and is the basis of the current inter-state system.
State-centric theorists of International Relations (realists and neorealists) study the inter-state system using the State as their focus. They do not underscore the importance of non-state actors, but for the sake of general applicability of the theory, they are abstracted away.
There are three powerful arguments for the study of the state. The first is that states have national interests and actively pursue them. Realists assume the national interest is state power, while neorealists assume it to be state survival at a minimum and state power at a maximum. Even though other theorists such as constructivists argue that there are a variety of different opinions among the populace regarding state policy, these opinions can be abstracted away for the sake of theory. This leads us to the second reason. The policies of the State are binding on all its citizens even if they affect different sections of the populations in different ways. States are sovereign entities with ultimate authority over their territories and populations. And, third, with no overarching authority above states, the ideal method of studying the system is at the level of the state. Although there has been a rise in global transnational actors on the international stage, they do not pose a threat to the role of the state. In fact, if necessary, the State can crack down on these actors in order to reassert its supremacy.
Even though there are certain features of the international system that these theories have not explored yet, the importance and centrality of the State in international relations cannot be questioned, at least in the foreseeable future.