The international balance received its classical exposition during the eighteenth century, about the time at which, largely during the struggle for independence of the American colonies, the idea of checks and balances within a government was elaborated. Although linked, the doctrines had important differences. The international balance existed, if at all, among similar entities, the recognized powers, which placed in the scale weights of the same kind—military power, actual or potential. It was the lack of any precedent and effective authority among nations that made the balance of power necessary. The threat of war maintained the balance, and sometimes war was needed to restore it. By contrast the domestic balance refined by the Founders was not among powers of the same sort, but among powers of different sorts. All these were derived from the people, who might limit, redistribute, or withdraw what they had given. And few believed that domestic society rested on the perpetual threat of strife.
It is not an accident that the doctrine of the balance of power—alike in international and in domestic politics—received its classic and most rigorous statements at a time when foreign policy was largely a matter for rulers who could use the war potential of their states for their own aggrandizement. It was because a ruler had to be able to wage effective war that he had to be allowed the armed force that contributed to his domestic control. British reliance on a navy rather than on a standing army was, and was known to be, important to the growth of British liberties—and later to American liberty. In a sense, therefore, the international balance of power was needed to check the pretensions of rulers who lacked any effective domestic check.
Many of the early American leaders, however, held the belief that in their new world a more just—a more perfect—society than that of Europe could be formed. Historians may differ about the degree to which that implied a regard for democracy. The tyrant people was hardly less to be feared than the tyrant king. But that sensible, rational men—men of property and standing—could cooperate for the common good, few doubted. To balance the servants of the public against each other was both a political safeguard and a political convenience, rendering excess less likely and vigilance less demanding. It was not a political necessity of the same order as the international balance of power. Americans quickly came to believe, and continued to believe through most of their history, that sound domestic institutions must bring sound foreign policies with them.
The balance of power, however, although it may act to restrain the actions of those who believe in the doctrine, is in the first instance a device to restrain others. Should not Americans, very conscious that other states were not founded on their own good principles, have been ready to consider contributing to the maintenance of an international balance when appropriate, more rather than less because their own domestic principles were sound? There is little evidence that they did consider doing so, and that fact may throw light on the limitations of the doctrine.
The revolutionary war itself provides an example of the balance of power in operation. A desire not to be involved in the European balance, not to be a weight in the British scale, had played an important part in the American demand for independence. It was the readiness of the allies in the coalition against Britain to abandon each other, and the readiness of Britain to calculate relative gains and losses, that made the outcome possible. Behind the behavior of all the parties in the American war lay a tacit agreement that American independence was acceptable—the Americans wanted to be removed from the British scale, the French and Spaniards wanted the colonies removed from the British scale, and on their side the British were finally convinced that that removal would not have disadvantages only. Such calculations may imply a large element of uncertainty as to how the independent United States would behave—Why should their independence weaken Britain more than their continued existence as disaffected colonies?—but in the event few of the negotiators had any doubt as to the only possible conclusion of the war.
For a short time after independence, Americans remembered that the European balance of power had played some part in their victory. George Washington's famous injunction against "excessive partiality for one foreign nation and excessive dislike of another" would hardly have been necessary had there been no Americans who wanted to align themselves either with Britain or with France. It would not have been uttered had American interests clearly required an alignment with either side. Yet in the political debates at the end of the eighteenth century there was already a large ideological element. Washington was not merely arguing that a due regard for the balance of power requires powers to hold themselves aloof until it is clear that the balance is about to tip, and then to place in the scale only such weight as is needed to adjust it. He was urging his countrymen not to take sides in European quarrels whose out-come could not affect the United States.