Discipline: Political Science
Theory of international relations.
Equality of power between nations is conducive to peace, since it constrains any one nation from engaging in war with another. Thus weak nations may be promoting general stability by arming, but strong nations may destabilize balance by continuing to arm.
The theory has in practice justified deeply complex calculations of comparative military advantage, particularly in relation to nuclear weapons.
Also see: collective security
David Robertson, The Penguin Dictionary of Politics (London, 1986)