International relations after the Second World War were shaped by two factors: (1) the emergence of two superpowers and the ideological conflict between two blocs of states, and (2) the „hypertrophy of war” created by the development of weapons of mass destruction. The end of the „cold war” did not terminate local wars, including wars fought by great powers against weaker adversaries. Understanding such wars requires an analysis of the decision-making process, including the consequences of misperception. Russian war against Ukraine can best be understood in terms of the need to legitimize an authoritarian regime by external success. The final outcome of the war will depend on political, rather than purely military factors. Since neither side is likely to achieve a full military victory, leadership change in the Russian Federation may become the way to end the war.