Balance of Power

Political theory stating that, in the absence of a central authority, states will tend to form balanced networks or coalitions. As the fortunes of nations rise and fall, so do their international political and military influence. Such changes often upset the existing distribution of political power among states, making some relatively more powerful than before and rendering others weaker. The history of political relations between states is marked by a continuing concern to maintain a balance of power to prevent the rise of a single dominant state or coalition.

Theory

Political theorists who subscribe to the principle known as realism endorse the view that survival has been the main concern of states or polities in any period in history. They further argue that states act rationally and will make sensible decisions that increase their chances of survival. The realist sees states operating in a system that lacks laws or norms to prevent states from attacking one another. Each state must fend for itself, without expecting assistance if it is attacked because all other states are quiet rivals if not active foes.

Great and Small Powers

If a state's capabilities are especially large compared to others, that state can be considered a great power. Such a power has the ability to threaten or conquer smaller, weaker states and take control over their resources. At a minimum, the strong state may exert an influence over the weaker state's behavior. If a state is not powerful, however, it needs to find a method to protect itself from threats by stronger powers. To do so, it may ally with another strong state or a larger coalition of smaller states, although both options have drawbacks. A strong ally may have the power to impose its will on its partners, or even turn against them. However, most small states have very limited armed forces capabilities, which could render even an alliance of many small powers militarily weak.

Great powers, however, have some capacity to defend themselves and to protect their interests. They rarely risk alliances with other strong states that might ultimately attack them or injure their interests. Those states with the most power will necessarily oppose one another because great powers are the only states that can pose significant threats to other great powers. Instead, great powers typically form alliances with smaller powers with which they share either mutual interests or a common foe. Thus, the balance among the leading powers directly touches many small powers as well. The nature of that power balance determines whether international relations will be characterized by conflict, cooperation, or détente.

Whether strong or weak, states are always concerned about their relative capabilities and position in the international system. States with roughly equal power positions are not concerned about their principal opponent acquiring a large number of weapons. They are, however, disturbed when an opponent obtains a greater number of weapons than the state possesses in its own arsenals. One state's gain is perceived by all the others as a loss.

Fundamentally, however, a balance of power is a safety mechanism. The Western European powers, in the 19th century in particular, believed that a proper balance of power provided stability and therefore security, and they promoted it actively. A balance of power raises the costs for an individual nation to act aggressively toward another because doing so risks retaliation by not only the target state but also its allies.

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