What are depature between classical and post 1945 system balance of power?

The main difference between the classical balance of power system and the post-1945 system is the shift from a multipolar world to a bipolar world.

In the classical balance of power system, power was distributed among multiple great powers, leading to a more complex and fluid system of alliances and rivalries. This system was characterized by frequent wars and shifting alliances as states sought to maintain a balance of power and prevent any one state from becoming too dominant.

In contrast, the post-1945 system was dominated by two superpowers, the United States and the Soviet Union, leading to a bipolar world order. This system was characterized by a stable balance of power between the two superpowers, as well as the development of nuclear weapons which deterred direct conflict between them.

Overall, the departure between the classical and post-1945 balance of power systems lies in the shift from a multipolar to a bipolar world order, which had significant implications for international relations and the nature of conflict during this period.