The Balance of Power and Spheres of Influence

The balance of power is among the oldest and most durable concepts in the study of international relations, describing the tendency of states to act, whether by conscious policy or systemic pressure, to prevent any single state or coalition from achieving overwhelming dominance over the others. The concept has clear roots in early modern European diplomacy: the Peace of Westphalia in 1648, which ended the Thirty Years' War and established the modern system of sovereign, formally equal territorial states, is conventionally treated by international relations scholars as the founding moment of the state system within which balance-of-power politics would operate for the following three centuries. The 18th-century European state system, and in particular the diplomacy surrounding the War of the Spanish Succession (1701-1714) and the subsequent Treaty of Utrecht of 1713, saw the balance of power explicitly invoked as a governing principle of interstate relations, aimed at preventing the union of the French and Spanish crowns under a single Bourbon monarch.