After the Second World War, the International System came to be a totally different system from the classical (19th century) international system. The classical international system was Euro-centric and it worked on the principles of balance of power, war as a means, secret diplomacy as an instrument, and narrow nationalism as its objective.

Under the impact of the two world wars, particularly as a result of the Second World War, the nature of the international system underwent a big change. Under the impact of the changes that it produced in the international power structure as well as due to the emergence of several new factors, the nature and content of post-war international relations registered an almost total and revolutionary change. It became a new international system and replaced the classical international system.

Changes in Post War International Relations:

1. End of the Traditional Euro-Centric International Power Structure:

The two wars, particularly the Second World War destroyed the old international power structure and gave rise to a new structure. Before the war, only European nations, particularly Britain, France, Germany and Italy, were the major actors in world politics. The USA used to follow isolationism and the USSR, after 1917, had remained fully occupied with the process of internal consolidation of the socialist system.

After the war:

(i) Germany and Italy became very weak as a result of their defeats in war;

(ii) Britain and France also became weak due to the heavy war losses suffered by them;

(iii) The war destroyed the balance of power system in Europe;

(iv) There appeared a power vacuum in Europe;

(v) Europe lost its position as the epicenter of international politics;

(vi) A weak Europe set the stage for the liberation of Asian and African countries from the clutches of imperialism and colonialism;

(vii) The power vacuum in Europe impelled the USA to abandon isolationism and to increase its influence in Europe.

(viii) It compelled the USSR to adopt a similar exercise for increasing its influence in international relations.

These post-war changed produced a big change in the international system.

2. Emergence of Cold War:

In the Post-war period, the USA decided to use its superior economic and military position for filling the power vacuum in Europe and for this end decided to win over the democratic European nations through its Marshall Plan. It also adopted the policy of fighting the spread of communism. ‘Containment of Communism’ became the primary aim of US Foreign Policy.

Such an American attempt was thoroughly opposed by the USSR and it also decided to extend its influence in Europe. The success that it achieved in exporting communism to most of the East European countries emboldened it. The emergence of China as a communist power in 1949 gave further strength to the Soviet-led communist movement. The USSR adopted the policy of challenging US policies. In the process, there developed a cold-war—a war of nerves full of tensions and strains in world politics, which made international peace a risky and unstable peace.

3. Emergence of Bipolarity—Bipolar Power Structure:

The emergence of the cold war led to the organization of two competing and rival camps by both the USA and the USSR. The USA floated a large number of bilateral and multilateral alliances like NATO, SEATO, ANZUS, and several others for consolidating the democratic anti-communist countries under its own leadership.

The USSR countered the move by organizing the communist countries into the Warsaw Pact. These developments led to the emergence of two rival camps—the US Bloc and the Soviet Bloc, This situation came to be characterized as bipolarity in world politics and it divided the world into two competing and even hostile blocs.

4. Rise of Several New Sovereign States:

After World War II, the weakened position of the European imperial powers and the strengthened spirit of national self- determination and liberation among the colonies became instrumental in initiating a process of end of colonialism and imperialism in the World. The anti-imperial & anti-colonial movement began registering a stupendous success.

Several nations of the world, particularly Asian and African nations, were successful in overthrowing the yoke of colonialism and imperialism and in securing their independence. There came to be a big increase in the number of sovereign states in the world. The rise of new sovereign states in Asia, and Africa and a resurgent Latin America began giving a completely new look to the world map and international relations.

5. Birth of Non-alignment:

In the era of the cold war and alliance politics, some states, particularly some new states, decided to remain away from the cold war and the superpower alliances. States like India, Yugoslavia, Egypt, and Sri Lanka. Burma (now Myanmar) and some others decided to follow such a policy. This comes to be known as the policy of Non-alignment.

In 1960 the countries following non-alignment in international relations launched the movement of the Non- aligned (NAM) for collectively withstanding the pressures of the era of the cold war by taking mutually accepted decisions and policies. The main aim of Non-alignment and NAM was both to keep away from the cold war and its alliances as well as to promote mutual understanding and cooperation among the non-aligned states.

6. Democratization of Foreign Policy and Changes in Diplomacy:

The end of the Second World War rejected the thesis of authoritarianism in favor of democracy and under its influence, the formulation and implementation of foreign policy became democratic in nature and style. In the 19th century, the foreign policy of a nation was formulated by a class of professional experts—the diplomat and statesman.

It used to be a close preserve of the Foreign Office and Diplomacy. The democratization of politics however made foreign policy an object of discussion and subjected it to the influence of the common man. National public opinion, press, and world public opinion came to be important factors of foreign policy.

The changes in the nature, content, and working of foreign policies of various nations resulted in a big change in the nature of post-war international relations. Diplomacy also came out of its old style and color and it now came to be new and open diplomacy.

7. Loss of Relevance of Balance of Power:

Between 1815-1914, Balance of Power acted as a regulator of International relations. It suffered a big blow in the First World War. It was revived in 1919, with a new mechanism like the League of Nations, but it again flopped in 1939 when the Second World War broke out.

After the end of the Second World War, several big structural changes in the International system as well in the Balance of Power system reduced the operation ability of this device. This rise of two superpowers, the transformation of war into a total war, the emergence of nuclear weapons, the establishment of the United Nations, the emergence of the process of decline of imperialism- colonialism, and several other such factors made the Balance of Power system almost obsolete.

8. The Birth of Nuclear Age:

The final end of the Second World War came with the use of atomic weapons by the USA against Japan. It symbolized the beginning of the nuclear age in International Politics. For the first time, some countries came to acquire means capable of destroying the entire world. The nuclear factor divided the nations into nuclear nations and non-nuclear nations, the former enjoying superiority in power relations over the latter.

The two superpowers came to enjoy, as Max Lerner observed, the capacity of “overkill”. Both, the U.S.A. and the U.S.S.R. could destroy the entire world but no other nation individually or collectively could destroy or defeat the superpowers. War became a total war and the world found itself dependent on the policies and activities of the two superpowers.

9. Transformation of War into Total War:

Nuclear weapons changed the nature of war from a Simple war to total war. These made the war totally destructive. No nation whether nuclear or non- nuclear, could hope to survive a future war since it was bound to be a thermo-nuclear war.

10. Balance of Terror in place of Balance of Power:

The traditional concept of balance of power became obsolete in the face of the fact that it became impossible to create a preponderance of power against any aggressor backed by nuclear power. The Balance of Power got replaced by a Balance of Terror which made the international system very dangerous and risky. The fear of mutually assured total destruction (MAD) through accidental war began haunting the policy-makers of all the nations.

11. A New Desire for Peace:

The two World Wars within a short span and the possibility of a much more destructive, rather totally destructive, Third World War made humankind highly conscious of the need for preserving and strengthening international peace and security. The urge for securing peace became stronger than ever before.

12. Increasing Interdependence among Nations:

After the end of the Second World War, International relations began developing a truly global character in which each nation began finding its national interests inseparably bound up with the interests of other nations as well as with international interests of peace, security and development. This realization and the growing interdependence of the world became instrumental in giving a vital and welcome strength to the cause of peaceful and cooperative international relations.

13. Birth of the UNO:

The failure of the League of Nations to maintain peace after the First World War was mostly due to the shortcomings of the Covenant of the League as well as because of the not fully representative character of the League. Consequently, after the Second World War, the statesmen felt no hesitation in agreement to establish a new international organization—the United Nations Organisation which came into existence on 24 October 1945.

The UNO was designed to act as an effective platform for international diplomacy designed to secure international peace and security, and development through collective efforts of all the nations. The UN assumed the responsibility to maintain international peace and security by promoting friendly cooperation among the member states. Along with it, the UN Charter laid down a collective security system as the new device of power management in international relations.

14. Recognition of the Role of Power in International Relations:

In the post-war period, the factor of power came to be accepted as an incontrovertible fact of international relations. It was realized that each nation is always prepared to use its national power to secure the goals of her national interest. It was further realized that the role of power in international relations was direct and the nature of interactions among nations reflected a continuous struggle for power. To analyze international politics as a struggle for power or as a set of interactions involving power, came to be a very popular approach in International Politics.

15. Emergence of the Age of Technology:

In the post-1945 years, man’s ability to use the knowledge of scientific inventions for the welfare of humankind got greatly enhanced. It was because of this fact that the 20th century came to be known as the age of technology. Science and Technology began playing a big role in changing the environment of international relations.

As a result of the technological revolution, there began appearing a revolutionary development in spheres of industry, transport, communications, agriculture, and military. The resultant economic growth became instrumental in producing big changes in the nature of international relations.

The change in the concept of war from a simple war to a total war gave a new dimension to international relations. The revolutionary developments in the fields of transport and communication increased the scope and frequency of relations among nations. The rapid technological development in the developed countries made them economically and militarily stronger enough to maintain a neo-colonial control over the newly emerged developing countries.

Their monopoly over advanced technology and the disinclination to share its benefits with all other nations produced sharp division between nations—the developed and the under-developed or developing nations. The relations between the developed and under-developed later on became a focal issue of post-1945 international relations.

16. Emergence of a Peace Movement:

The two World Wars within a short duration and the possibility of a much more destructive, rather totally destructive Third World War made humankind highly conscious of the need for preserving and strengthening international peace and security. The urge for securing peace became stronger than ever before. There appeared a welcome peace movement in international relations. This encouraged nations to work for mutual welfare and development. They became highly conscious of the need for development through mutual cooperation and goodwill.

17. Rapidly Increasing Interdependence among Nations:

After the end of the Second World War, international relations began developing a truly global character in which each nation began finding its national interests inseparably bound up with the interests of all other nations as well as with international interests of peace, security, and development.

This realization and the interdependent nature of the international community became instrumental in giving a vital and welcome strength to the cause of peaceful and orderly international relations. Peace became a cherished value and it gave a purpose to international relations i.e. to find ways and means for securing and strengthening stable and durable peace in the world. These gave an encouraging and welcome direction to post-war international relations.

18. End of the Traditional International System:

The international system of the post-war period became totally different from the classical international system in several ways:

(1) Power scarcity that characterized the classical international system got replaced by power surplus (Nuclear weapons, overkill capacity, and two superpowers) in the new system.

(2) The Balance of power got replaced by a Balance of Terror.

(3) The formulation and implementation of foreign policy became a more complicated and democratic exercise.

(4) A big change in world political relations took place as a result of the rise of new states, and the liquidation of imperialism and colonialism.

(5) Peace, security, development, and prosperity for all the nations got recognized as a value in international relations.

(6) There developed an arms race between the two superpowers and the exercise became more dangerous because of the birth of the nuclear arms race.

(7) Because of the increase in the number of states, there came to be developed several new problems and international relations became highly complex.

(8) The presence of the United Nations gave a new look to the post-war international system.

(9) New and Open Diplomacy came to replace the old and secret diplomacy.

(10) The presence of two competing, in fact, rival superpowers set the stage for the emergence of the cold war and bi-polarity in international relations.

(11) The transformation of war into a total war made it much more dreaded and the nations became more and more interested in preserving international peace and security.

(12) All the nations became conscious of the need for preserving peace through a better and effective device of power management i.e. collective security.

Thus the Second World War had a big impact on the nature of international relations. The post-War International system came to be a system totally different from the pre-war international system.

After the Second World War, the International System came to be a totally different system from the classical (19th century) international system. The classical international system was Euro-centric and it worked on the principles of balance of power, war as a means, secret diplomacy as an instrument, and narrow nationalism as its objective.

It came to be replaced by a new international system which was characterized by two superpowers, the cold war, bipolarity, non-alignment, anti-imperialism, the UNO, the presence of several new sovereign states in the world, N-weapons, and the threat of Total War. This new international system continued to work, almost unchanged, till the last decade of the 20th century when it came to be a Post-Cold War, Unipolar International System experiencing a new liberalization and globalization.