The Darwin of international relations
By Ken Booth
It is difficult to imagine the academic study of international relations today in the absence of the work of Ken Waltz. There can be little doubt, even on the part of his critics, that he has been the single most significant figure in our field in the postwar era.
Waltz is to the study of international relations what Darwin is to the study of biology. I make this claim in terms of the sheer intellectual significance of his theoretical contribution. One cannot make sense of the biological world apart from Darwin's theory of evolution: equally, Waltz's structural framework for understanding how states interact under anarchy, with an uneven distribution of power and a desire to survive, offers a powerful theory for making sense of the international system. Neither theory explains everything in their domain -- one always needs to know more about particularities -- but both provide compelling big-picture explanations of their domains.
Waltz wrote few books over a long career. He liked to say that "we don't need more books, we need better ones," and he practiced what he preached. Man, the State, and War (1959) and Theory of International Politics (1979) are both classics, with time-transcending significance and influence. The levels-of-analysis approach to the causes of war in the earlier book was a decisive contribution to grappling with the discipline's traditional core problematic, while the "parsimonious" theory in the later book had a profound impact throughout the discipline.
Nobody has influenced the field as deeply or in as many directions as Ken Waltz. Disciples and critics alike are his offspring, whether their work has been to refine and develop his ideas (new schools of realism and liberalism) or to try to think outside the Waltzian world (some constructivism and critical theory). By persuasion and provocation, he lifted the discipline to a new level.
Waltz was a stubborn defender of his theory, of course, but he did not over-claim. He was not a structural determinist, nor did he think his theory necessarily timeless. In particular, he emphasized that his was a "systemic theory" of international politics, not a "reductionist theory" of foreign policy. In other words, Waltz's theory of the international system did not tell us how the individual units in their foreign and defense policies would behave -- though he had his own clear ideas about the sorts of behavior the system would reward or punish. His views about the positive utility of the controlled spread of nuclear weapons, for example, were particularly controversial.
The debates generated by Waltz's work have made the IR discipline what it is today. His work, like that of other "realists" once thought past their sell-by dates, has been and is being re-thought. We still have much to learn from him, and in that regard Ken Waltz's influence will live on not simply through his writings but through his impact on individual lives -- as a remarkable teacher, a human being who attracted loyalty, a generous friend, an intellectual giant, and a professional role model for all who knew him. He was and will remain our indispensable theorist.
Ken Booth FBA is editor of International Relations, formerly chair of the British International Studies Association, and E.H. Carr Professor in the Department of International Politics at Aberystwyth University.