This paper deals with theoretical approaches to understanding of the contemporary world order. In particular, three approaches are analysed: confrontational fatalist, cooperative mitigationist, and consensual radical, each one with its own logic. The fatalist approach, inherited from the past, is rooted in  the  logic  of  confrontation.  According  to  this  logic,  mutual  distrust  among  states  leads  to  power balancing and inevitable wars, which make the core of the contemporary world order. The mitigator approach derives from the logic of cooperation among states, which resort to international institutions to mitigate the fear of one another. According to this logic, mutual participation in international regimes and organizations helps to reduce uncertainty in interstate relations. The third approach, aimed to the future, involves the logic of consensus. According to this logic, mutual distrust between nation-states can be transcended by eradication of the nation-state as such. Taken non-Western societies for example, the paper demonstrates how political, economic, social, and cultural challenges transform the contemporary system of international relations, eroding the notion of state sovereignty. At the same time, many countries actively resist these processes by diplomatic means, trying to rescue the Westphalian world order. However, the author suggests that diplomacy may suspend but not reverse the natural process of the Modern world order erosion, which gives way to a new, post-Modern one. The new world order will be based on interdependence, that means nation-states loosing their sovereignty in favour of international institutions. The need of the new world order is proved by global challenges like terrorism, nuclear proliferation, poverty, hunger, epidemics, forced and illegal migration, trade in people, child labour, sex industry, gender discrimination, which no state (including the USA and their close allies) is able to resist on its own.