||Theories which describe conditions of equilibrium in political systems are called â€˜balance of powerâ€™ theories. They can be divided into those which describe stability within internal (or domestic) political systems and those which refer to external or international systems.
Internal balance of power theories describe the political process through which certain parties and interest groups influence the allocation of resources or access to political power.
International balance of power theories focus on the mechanisms which are used to prevent war or aggression between and among sovereign states, the key idea being that wars are caused by a disruption of the existing balance of power. Debate among historians and political theorists has centred on whether or not a single hegemon (or dominant power) is necessary to prevent war and whether (and how) deterrence is essential to the preservation of stability in international relations. The relations between the â€˜great powersâ€™ between 1815 and 1945 remain the subject of controversy for balance of power theorists.
The development of deterrence theory underwent a significant change following the development of weapons of mass destruction such as hydrogen and atomic bombs. The emergence of two ideologically opposed nuclear superpowers (the USA and USSR) led to a change from a balance of power based on simple deterrence to an arms race based on each side\'s determination to hold a balance of terror, or an offensive capability to destroy or annihilate the opposing power. The escalating arms race led to a further development in deterrence theory known as â€˜mutually assured destructionâ€™ (MAD) in which each side was convinced that no pre-emptive nuclear strike would be sufficient to prevent the other from retaliating with a sufficiently massive force which would ensure total, immediate and mutual destruction.
The costs of this arms race, which appears to have ended in 1991, has been a significant factor in the economic decline of both superpowers; it left the US economically weakened and contributed to the disintegration of the USSR. Although the USA remains the world\'s dominant military power the decline in the ideological cleavage between capitalism and communism has led to a new form of balance of power, based primarily on economic interdependence rather than pure military strength. A multi-polar balance of power is emerging, based on a revitalized western Europe, Japan and China, economic superpowers which can partially offset the combined military and economic power of the US.
Whether the relative stability of the bipolar balance of power during the cold war, at least in the â€˜Northâ€™ of the world, will be maintained in the emergent multi-polar world remains to be seen. BO\'L
See also pluralism.Further reading Robert Keohane, After Hegemony; , R. Pettman, International Politics: Balance of Power, Balance of Productivity, Balance of Ideologies.