Thesis deals with the issue of the conceptualization of the post-Westphalia world system by using the New Middle Age theory with focus on its geopolitical aspects. First the theoretical concepts concerning state, sovereignty, and the basis of the neomedievalist world view are tackled. After creating a theoretical tool to assess the appearance of the neomedieval world order we apply the criteria on four selected case studies - Somalia as an example of failed state, Pakistan as failing state, the European Union as a supra-state entity, and the People's Democratic Republic of Korea as a classical example of Westphalia-type state. In the conclusion the four case studies are brought together and our findings lead to the creation of an analytical tool which can be used for understanding basic geopolitical issues of different territories.