1. It has even been employed as a basic concept by some historians. See, for example, Kennedy, Paul, The Rise and Fall of the Great Powers (New York: Random House, 1987)Google Scholar; and Gaddis, John, “The Long Peace: Elements of Stability in the Postwar International System,” in Lynn-Jones, S. M., ed., The Cold War and After: Prospects for Peace (Cambridge, Mass: MIT Press, 1991).Google Scholar

2. Waltz, Kenneth, “The Stability of a Bipolar World,” Daedalus 93 (Summer 1964) pp. 881–909.Google Scholar The quotation is drawn from p. 886.

3. Waltz seems to have changed his views on this question over the years. In his original article on bipolarity, he suggested that a multipolar world of nuclear powers would be a dangerous and unstable place. More recently, however, he has argued that the spread of nuclear weapons likely would have a stabilizing influence on international politics; see Waltz, Kenneth, The Spread of Nuclear Weapons. More May be Better, Adelphi Papers No. 171 (London: International Institute of Strategic Studies, 1981Google Scholar). For a representative collection of articles that discuss the effect of the end of bipolarity on the likelihood of war, see Sean M. Lynn-Jones, The Cold War and After.

4. Waltz has been especially insistent on (1) the importance of distinguishing between describing the behavior of states and explaining it and (2) the significance of bipolarity in explaining some of the most important features of state behavior since World War II. See Waltz, Kenneth, Theory of International Politics (Reading, Mass.: Addison-Wesley, 1979).Google Scholar

5. Lippmann, Walter, The Cold War: A Study in U.S. Foreign Policy (New York: Harper Torchbooks, 1972Google Scholar). Lippmann's book first appeared as a series of newspaper articles criticizing George Kennan's famous article (which was written under the pseudonym “X’) called “The Sources of Soviet Conduct.” Kennan's article was, of course, where the idea of containment was first sketched out for the general public.

6. For a discussion of the relation between the failure to agree on the future of Germany and the initiation of the cold war, see Wagner, R. Harrison, “The Decision to Divide Germany and the Origins of the Cold War,” International Studies Quarterly 24 (06 1980), pp. 155–190.CrossRefGoogle Scholar

7. Lippmann, , The Cold War, pp. 51–52.Google Scholar

8. See Waltz, “The Stability of a Bipolar World.’

9. Burns, Arthur Lee, “From Balance to Deterrence: A Theoretical Analysis,” World Politics 9 (07 1964), pp. 494–529.CrossRefGoogle Scholar

10. Waltz, , Theory of International Politics, pp. 180–81.Google Scholar

11. Waltz, , Theory of International Politics, pp. 181–82.Google Scholar

12. See Herz, John, International Politics in the Atomic Age (New York: Columbia University Press, 1959Google Scholar). Herz claimed that bipolarity, in addition to abolishing the traditional balance-of-power mechanism of shifting alliances, had led to a diminution in the sovereignty of states that were associated with the two superpowers. This was true not only for satellites of the Soviet Union but also for allies of the United States, as evidenced by certain provisions of the agreements that governed stationing U.S. troops abroad. Herz claimed that those provisions compromised the territorial integrity of the allies (pp. 111–43).

13. However, discussions about the significance of the end of bipolarity often associate the North Atlantic Treaty Organization (NATO) with the bipolarity of the postwar system; see, for example, Gaddis, “The Long Peace,” p. 11; and John Mearsheimer, “Back to the Future: Instability in Europe After the Cold War,” in Lynn-Jones, , The Cold War and After, pp. 141–43.Google Scholar Thus, some writers apparently believe there is a relation between polarization and a bipolar power distribution. As we shall see, there is a good reason for this. Nonetheless, the reasons why polarization appears benign rather than dangerous seem to be those articulated by Waltz, based on the concentration of power in the United States and the Soviet Union.

14. Waltz, , Theory of International Politics, p. 131.Google Scholar

15. Waltz, , Theory of International Politics, pp. 130–31.Google Scholar For another example, see Snyder, Glenn and Diesing, Paul, Conflict Among Nations: Bargaining, Decision Making, and System Structure in International Crises (Princeton, N.J.: Princeton University Press, 1977), pp. 28–29.Google Scholar My discussion is focused so heavily on Waltz's writings because no one has discussed the issues with which I am concerned more extensively than he. Further, no one I know of has written anything on the subject that is not open to the same criticisms levied against Waltz. Thus, if Waltz's discussion is not satisfactory, we can be sure that no one els's is either. The skeptical reader can easily check this by first, looking carefully at how the distinction between bipolarity and multipolarity has been defined by other writers; second, checking to see what properties these writers have attributed to bipolar systems; and third, examining how those properties have been derived from the definition. Attention to that last question will reveal that Waltz was correct in claiming that many discussions of this subject merely describe state behavior without attempting to explain it. Examples of writings of this sort include Morton Kaplan, System and Process in International Politics (New York: John Wiley and Sons, 1957), pp. 36–45Google Scholar; and Raymond on, Peace and War: A Theory of International Relations (New York: Frederick A. Praeger, 1967), pp. 136–49.Google Scholar

16. This is an example of using one definition of a term to derive some conclusions and another definition to derive others.

17. Levy, Jack, “The Polarity of the System and International Stability: An Empirical Analysis,” in Sabrosky, Alan Ned, ed., Polarity and War: The Changing Structure of International Conflict (Boulder, Colo.: Westview Press, 1985).Google Scholar

18. Hopf, Ted, “Polarity, the Offense–Defense Balance, and War,” American Political Science Review 85 (06 1991), pp. 475–94.CrossRefGoogle Scholar

19. Waltz, , Theory of International Politics, p. 163.Google Scholar

20. Waltz, , Theory of International Politics, p. 199.Google Scholar

21. The earliest use of the term “bipolarity” that I have found is in Fox's, William T. R. book, The Super powers: The United States, Britain, and the Soviet Union—Their Responsibility for Peace (New York: Harcourt, Brace, and Company, 1944), pp. 97–98.Google Scholar (Note that according to Fox, there would be three superpowers after the war: the United States, the Soviet Union, and Britain; he called them “super-powers” because of their influence in more than region.) By “bipolarity,” Fox meant the dominance of international politics by the Anglo–American alliance on the one hand and the Soviet Union on the other, and he believed that “a ‘tripolar’ system” was “not … beyond the realm of possibility.” If it developed, it would be because the three superpowers could not agree on controlling Germany, which would lead to its emergence as a third “pole.” Thus, Fox saw only two possibilities: superpower agreement and the postwar control of Germany, or superpower disagreement and the re-emergence of Germany as a major power. He overlooked the possibility that Germany would be divided as a result of the inability of the superpowers to agree on how it should be controlled. I am grateful to Robert Friedheim for reminding me of the relevance of Fox's book.

22. In discussions of this question, there is a tendency to confuse the state of the world in 1945, when many countries lay prostrate from the effects of World War II, with conditions in, say, 1970, by which time the countries that had participated in World War II had recovered, although the world was still considered to be bipolar.

23. Waltz, , Theory of International Politics, pp. 179–80.Google Scholar

24. Hopf, relying on a remark by Waltz, defines a bipolar system as one in which “no third power” is “able to challenge the top two”; see Hopf, “Polarity, the Offense–Defense Balance, and War,” p. 478. Nevertheless, this leaves unclear what sort of challenge might be made by alliances of lesser states. It is also not clear what “being able to challenge” means.

25. Waltz, , Theory of International Politics, p. 169.Google Scholar

26. Moreover, France did not withdraw from the North Atlantic alliance; it merely withdrew its forces from the NATO integrated command.

27. Waltz, “The Stability of a Bipolar World,” p. 903.

28. For one of the very few explicit discussions of this question (though one that does not explore implications for the meaning of “bipolarity”) see Art, Robert, “A Defensible Defense: America's Grand Strategy After the Cold War,” International Security 14 (Spring 1991), pp. 5–53.CrossRefGoogle Scholar

29. Morgenthau, Hans, Politics Among Nations: The Struggle for Power and Peace, 4th ed. (New York, Alfred A. Knopf, 1966), p. 336.Google Scholar

30. Morgenthau, , Politics Among Nations, p. 345.Google Scholar

31. See especially Inis Claude, Power and International Relations (New York: Random House, 1962), pp. 11–93Google Scholar; and Blainey, Geoffrey, The Causes of War, 3d ed. (New York: The Free Press, 1988), pp. 108–24.CrossRefGoogle Scholar For a recent discussion, see R. Harrison Wagner, “Peace, War, and the Balance of Power,” presented at the annual meeting of the American Political Science Association, Chicago, III., 3–6 September 1992.

32. This problem is discussed in Wagner, R. Harrison, “The Theory of Games and the Balance of Power,” World Politics 38 (07 1986), pp. 546–73CrossRefGoogle Scholar; and Wagner, “Peace, War, and the Balance of Power.”

33. Waltz, , Theory of International Politics, p. 168.Google Scholar

34. See, for example, Kaplan, , System and Process in International Politics, pp. 22–36Google Scholar; Aron, , Peace and War, pp. 151–53Google Scholar; and Niou, Emerson, Ordeshook, Peter, and Rose, Gregory, The Balance of Power (New York: Cambridge University Press, 1989), p. 76.CrossRefGoogle Scholar

35. This sort of system, as well as the following example, is discussed in Wagner, “The Theory of Games and the Balance of Power.” See also Niou, Ordeshook, and Rose, The Balance of Power, and Niou, Emerson and Ordeshook, Peter, “Stability in Anarchic International Systems,” American Political Science Review 84 (12 1990), pp. 1207–34.CrossRefGoogle Scholar

36. Thus, when no state is close to hegemony, Stephen Walt's distinction between “balancing” and “bandwagoning” is not clearly defined. See Walt, Stephen, The Origins of Alliances (Ithaca, N.Y.: 1987Google Scholar). This is one motivation for his distinction between balancing against “power” and balancing against “threats.” For a fuller discussion, see Wagner, “Peace, War, and the Balance of Power.”

37. In order to focus on the issue of system stability rather than peace, I assumed in my article on the balance of power that the outcomes of wars could be known with certainty, but resources could only be transferred by war; I thus avoided the issue of whether peaceful settlements could substitute for war (see Wagner, “The Theory of Games and the Balance of Power.”) Niou and Ordeshook, in their various explorations of the same problem, assume that potential victims can always avoid war by preemptively transferring resources to the attacking states; they also assume that the outcomes of wars can be anticipated with certainty (see Niou and Ordeshook, “Stability in Anarchic International Systems,” and Niou, Ordeshook, and Rose, The Balance of Power). Neither set of assumptions is adequate for examining the causes of war.

38. Note that what is important are the expectations that political leaders have concerning the outcomes of possible conventional wars. The resources (or “power”) of states comprise any assets they have that might influence the probability of their winning such a military contest. For a more extensive discussion, see Wagner, “Peace, War, and the Balance of Power.”

39. See, for example, the historical discussion in Morgenthau, , Politics Among Nations, pp. 196–205.Google Scholar

40. In a world of more than two states, coalitions as well as individual states can be a threat. This is much too complex a subject to be discussed adequately here. For a fuller discussion, see Wagner, “Peace, War, and the Balance of Power.”

41. I should emphasize that I do not mean to suggest that the numbers in the simple example discussed above would correspond to any of the standard ways of measuring the post–World War II distribution of power. (See, for example, Walt, , The Origins of Alliances, pp. 274–76Google Scholar). What is important is that the Soviet Union was sufficiently close to military dominance of the Eurasian continent that a stable coalition formed to oppose it. Nor does this explanation imply that there was no room for disagreement about how big a threat the Soviet Union posed. Indeed, it is precisely because of such uncertainty that controversies about how to understand the post–World War II balance of power were part of the cold war itself. This point is discussed further below.

42. See, for example, Nicholas Spykman's remarkably prescient discussion of the post–World War II balance of power in his book America's Strategy in World Politics: The United States and the Balance of Power (New York: Harcourt, Brace, and Company, 1942), pp. 446–72.Google Scholar At a time when the United States was at war with Germany and Japan, Spykman foresaw the need to reconstruct Germany as a counterweight to the Soviet Union, since a “Russian state from the Urals to the North Sea can be no great improvement over a German state from the North Sea to the Urals” (p. 460), as well as the need to defend Japan against any strong power on the Asian mainland (p. 470). Spykman, however, like everyone else, expected World War II to end like World War I, with the United States tempted to return to isolation. “It might be more in harmony with the nature of totalitarian warfare,” he wrote, “and provide a better transition to other forms of power struggle, if a scheme could be devised for the termination of the military conflict without a peace treaty” (p. 464). This, of course, is exactly what happened.

43. Waltz, , Theory of International Politics, pp. 168–69.Google Scholar

44. Waltz also exaggerates the importance of Germany's commitment to Austria prior to World War I, relative to German uncertainty about what England would do if war broke out. See Levy, Jack, “Preferences, Constraints, and Choices in July 1914,” International Security 15 (Winter 1990), pp. 151–86.CrossRefGoogle Scholar

45. As Stephen Walt has written, “More than anything else, the Cold War between the United States and the Soviet Union has been a competition for allies.” See Walt, , The Origins of Alliances, p. 3.Google Scholar

46. Morgenthau, , Politics Among Nations, p. 336.Google Scholar

47. The last question, of course, was one of the issues in the original critique of the notion of containment by Lippmann. For a discussion of this question in the context of the Middle East, see Walt, , The Origins of Alliances, pp. 147–180.Google Scholar

48. Walt assumes that indexes such as population and GNP are adequate measures of the power of states and ignores the uncertainty involved in anticipating the outcomes of wars based on such information alone. Thus, he concludes that the coalitions that formed against both the axis powers and the Soviet Union were much larger than is compatible with balance-of-power theory (see Walt, , The Origins of Alliances, pp. 262–85Google Scholar). This reasoning ignores the fact that the resources of the United States are located in the Western Hemisphere and not on the Eurasian continent, and that uncertainty provides ample motivation for states to seek as large a concentration of power against their opponents as possible (see Morgenthau, , Politics Among Nations, pp. 196–205Google Scholar). Walt also fails to give adequate weight to the facts that first, the great power of the United States gives its allies reason to worry whether such power will be used to protect them and second, that relying on U.S. protection that is not forthcoming can be dangerous. For all these reasons, Walt understates the relevance of balance-of-power theory to an explanation of the conflict between the United States and the Soviet Union. Moreover, in his extended discussion of balance-of-power theory, Walt refers several times to the “bipolarity” of the international system during the cold war but never defines the term or indicates its relation to balance-of-power theory.

49. Burns, “From Balance to Deterrence,” p. 509.

50. ibid., p. 520.

51. On the other hand, a nuclear second strike by the attacking state would destroy much of the object of its attack; and as the attacking state's troops advanced, they would become more vulnerable to their own government's nuclear strike. Thus, one could argue that the credibility of a threat of nuclear retaliation as a means of protection against conventional attack is greatest when the enemy desires to capture a state's assets rather than destroy them and is on the verge of success.

52. Herz, , International Politics in the Atomic Age, p. 189.Google Scholar

53. Actually, this is an oversimplification, since it is possible for a coalition of states to threaten the ability of others to protect their independence (see Wagner, “Peace, War, and the Balance of Power”). While I have focused on the positions first of Germany and then of the Soviet Union in Europe, the alliances between Germany and Japan and between the Soviet Union and China magnified the significance of European developments for the global balance of power.

54. For a fuller discussion, see Wagner, “Peace, War, and the Balance of Power.” Unfortunately, this shorthand terminology invites confusion with Kaplan's quite different distinction between “loose” and “tight” bipolar systems (see Kaplan, , System and Process in International Politics, pp. 36–45).Google Scholar

55. As discussed above, however, because of uncertainty and geography, the polarization that characterized Europe until the end of the cold war was not as complete in other regions of the world.

56. For a discussion, see the essays in Keohane, Robert, ed., Neorealism and Its Critics (New York: Columbia University Press, 1986).Google Scholar

57. See the discussion in Wagner, R. Harrison, “The Concept of Power and the Study of Politics,” in Bell, Roderick, Edwards, David, and Wagner, R. Harrison, eds., Political Power: A Reader in Theory and Research (New York: The Free Press, 1969), pp. 3–12.Google Scholar

58. This ambiguity leads to similar confusion about the relation between Britain's hegemony in the latter half of the nineteenth century and the nineteenth-century balance of power. For a discussion, see Gilpin, Robert, War and Change in World Politics (Princeton, N.J.: Princeton University Press, 1981).CrossRefGoogle Scholar

59. See, for example, Gaddis, “The Long Peace,” who accepts Waltz's thesis, and Stephen Van Evera, “Primed for Peace: Europe After the Cold War,” in Lynn-Jones, , The Cold War and After, pp. 193–243Google Scholar, who questions it. For important earlier discussions of this issue, see Deutsch, Karl and Singer, J. David, “Multipolar Systems and International Stability,” World Politics 16 (04 1964), pp. 390–406CrossRefGoogle Scholar; and Rosecrance, Richard, “Bipolarity, Multipolarity, and the Future,” Journal of Conflict Resolution 10 (09 1966), pp. 314–27.CrossRefGoogle Scholar All these discussions suffer from a lack of a clear definition of “bipolarity,” and therefore a lack of clarity about what is supposed to follow from what.

60. Waltz accepted the common view that World War I was made more likely by the freezing of alliance relationships among the European states. A proper understanding of the relation between the post–World War II distribution of power and the “long peace” of the postwar period raises serious questions about that interpretation; see Wagner, “Peace, War, and the Balance of Power.”

61. Van Evera, in his critique of the claim that bipolar systems are more peaceful than multi-polar ones, tends to confuse “balancing,” that is, the formation of defensive coalitions in opposition to the expansion of large states, with deterrence (Van Evera, “Primed for Peace,” pp. 219–26). Germany and Japan were defeated by a coalition that was overwhelmingly more powerful; but while that coalition won the war, it did not form in time to prevent it. Exactly the same thing could be said about the recent war in the Persian Gulf.

62. For a representative discussion, see Nye, Joseph, Bound to Lead: The Changing Nature of American Power (New York: Basic Books, 1990), pp. 234–37.Google Scholar

63. See Wagner, “Peace, War, and the Balance of Power”.