Kenneth Neal Waltz (born June 8, 1924 – May 13, 2013) was an American political scientist who was a member of the faculty at both the University of California, Berkeley and Columbia University and one of the most prominent scholars in the field of international relations. He was a founder of neorealism, or structural realism, in international relations theory. Waltz's theories have been extensively debated within the field of international relations. In 1981, Waltz published a monograph arguing that the proliferation of nuclear weapons would increase the probability of international peace.

Levels of analysis

Waltz's initial contribution to the field of political science was his 1959 book, Man, the State, and War, which classified theories of the causes of war into three categories, or levels of analysis. Waltz's refers to these levels of analysis as "images," and uses the writings of one or more classic political philosophers to outline the major points of each image. Each image is given two chapters: the first mainly uses the classical philosopher's writings to describe what that image says about the cause of war; the second usually consists of Waltz's analyzing the strengths and weaknesses of that image.

The first image argues that wars as caused primarily by the nature of particular individuals such as state leaders- think Napoleon or Hitler- or by human nature more generally. This is basically consistent with Classical Realism, which dominated the International Relations discipline at the time of Man, the State, and War but which Waltz would refute more fully in his next book, Theory of International Politics.

Theories of war that fall under the rubric of Waltz's second image contend that wars are caused by the domestic makeup of states. A prime example that Waltz's refers to is Lenin's theory of imperialism, which posits that the main cause of war is rooted in the need for capitalist states to continue opening up new markets in order to perpetuate their economic system at home. A more familiar example in the Western world today is the notion that non-democratic states, because of their internal composition, start wars.

Waltz ultimately rejects the first two images as being, if not completely unimportant, far less persuasive than the third image. The third image posits that the cause of war is found at the systemic level; namely, that the anarchic structure of the international system is the root cause of war. In this context, "anarchy" is not defined as a condition of chaos or disorder but rather one in which there is no sovereign body that governs the interactions between autonomous nation-states. Put differently, unlike in domestic society where citizens can theoretically rely on law enforcement agencies to protect their persons and property, if a state is invaded and calls "911" it can't be sure anyone will answer. Similarly, whereas when two citizens have a dispute they can appeal to the courts to render a verdict and, more importantly, the law enforcement agencies to enforce the court's ruling, there is no body above nation-states that is capable of: establishing rules or laws for all the states, deciding how these apply in specific cases, and compelling the states to honor the court's ruling. As a result, if an issue at stake is important enough to a state, it can only achieve a satisfactory outcome by using its power to impose its will on another state(s). The realization that, at any point in time any state can resort to armed force, forces each state always be prepared for that contingency. These themes are fleshed out more fully in Theory of International Politics which, as the title suggests, lays out a theory for international politics as a whole rather than the narrower focus on what causes war.

Neorealism

Waltz's key contribution to the realm of political science is in the creation of neorealism (or structural realism, as he calls it), a theory of International Relations which posits that the interaction of sovereign states can be explained by the pressures exerted on them by the anarchic structure of the international system, which limits and constrains their choices. Neorealism thus aims to explain recurring patterns in international relations, such as why relations between Sparta and Athens resembled those between the U.S. and the USSR in some important ways.

Waltz emphasizes repeatedly in this book and elsewhere that he is not creating a theory of foreign policy, which aims to explain the behavior or actions of a particular state at a specific time or throughout a period. A sizable amount of criticism of Waltz's balance-of-power theory has been made by scholars who find it unsatisfactory in explaining the foreign policy choices of particular states or in particular areas like nuclear proliferation.

Waltz argues that the world exists in a state of perpetual international anarchy. Waltz distinguishes the anarchy of the international environment from the order of the domestic one. In the domestic realm, all actors may appeal to, and be compelled by, a central authority - 'the state' or 'the government' - but in the international realm, no such source of order exists. The anarchy of international politics – its lack of a central enforcer – means that states must act in a way that ensures their security above all, or else risk falling behind. This is a fundamental fact of political life faced by democracies and dictatorships alike: except in rare cases, they cannot count on the good will of others to help them, so they must always be ready to fend for themselves.

Like most neorealists Waltz accepts that globalization is posing new challenges to states, but he does not believe states are being replaced, because no other non-state actor can equal the capabilities of the state. Waltz has suggested that globalization is a fad of the 1990s and if anything the role of the state has expanded its functions in response to global transformations.

Neorealism was Waltz's response to what he saw as the deficiencies of classical realism. Although the terms are sometimes used interchangeably, neorealism and realism have a number of fundamental differences. The main distinction between the two theories is that classical realism puts human nature, or the urge to dominate, at the center of its explanation for war, while neorealism stakes no claim on human nature and argues instead that the pressures of anarchy shape outcomes regardless of human nature or domestic regimes.

Waltz's theory, as he explicitly makes clear in "Theory of International Politics", is not a theory of foreign policy and does not attempt to predict or explain specific state actions, such as the collapse of the Soviet Union. The theory explains only general principles of behavior that govern relations between states in an anarchic international system, rather than specific actions. These recurring principles of behavior include balancing of power (the theory was revised by Stephen Walt, modifying the "balance of power" concept to "balance of threat"), entering into individually sub-optimal arms races, and exercising restraint in proportion to relative power. In Theory of International Politics (1979:6) Waltz suggests that explanation rather than prediction is expected from a good social science theory, since social scientists cannot run controlled experiments that give the natural sciences so much predictive power.

Bibliography

• Man, the State, and War. Columbia University Press. New York: 1959.
• Foreign Policy and Democratic Politics: The American and British Experience. Little, Brown and Company. New York: 1967.
• Theory of International Politics. McGraw Hill. New York: 1979.
• The Use of Force: Military Power and International Politics. University Press of America. New York: 1983. (coauthored with Robert Art).
• "Reflections on Theory of International Politics. A Response to My Critics" in: Keohane, Robert: Neorealism and Its Critics. 1986.
• The Spread of Nuclear Weapons: A Debate Renewed. W. W. Norton & Company. New York: 1995.
• Realism and International Politics. Routledge. 2008.

• In Man, the State, and War, Waltz proposes a three-images view of looking at international relations behavior. The first image was the individual and human nature; the second image the nation-state, and the third image the international system.

• In Theory of International Politics, Waltz elaborates many of the core principles of neorealist international relations theory, adopting a structural perspective that sets him apart from earlier (classical) realists like E.H. Carr and Hans Morgenthau, and later giving rise to the Neoclassical realist movement (Randall Schweller, Fareed Zakaria, William C. Wohlforth, Thomas J. Christensen, etc.) which tries to incorporate a structural component while emphasizing the state-society relationship that mitigates structural forces. (This book also popularized the term bandwagoning.)

• In The Spread of Nuclear Weapons: A Debate Renewed, Waltz argues for the virtues of a world with more nuclear weapon states because of their power in nuclear deterrence. Sagan argued against the proliferation of nuclear weapons. See nuclear peace.