The best account I have seen of why Kenneth Waltz was such an important figure:
In the 1960s and 70s, the classical realists were hounded by behaviouralists, systems analysts, game theorists, neo-functionalists and institutionalists, and pushed out of the theoretical mainstream. Thinkers like Morton Kaplan, Anatol Rapoport, Ernst Haas, Joseph Nye and Robert O. Keohane came to the fore, displacing the realists and shifting the core concerns of the field away from issues of human nature and power politics.
What Waltz did in this context was remarkable: almost single-handedly, he resuscitated realism, amputating those parts that were clearly dysfunctional, giving it the transfusions of new thinking that it needed, and returning it, revivified, to the fray.
Some complained he threw baby out with the bathwater.
Theory of International Politics shifted realism away from metaphysical speculation on human nature and onto firmer ground by removing any need for a philosophical anthropology to explain why international relations are as they are. Instead of a contentious account of ‘man’, Waltz substituted a structural account of the international system that borrowed heavily from the theory of the firm in classical economics.
There is another way of thinking about human nature: not metaphysical speculation or philosophical anthropology, but the evolutionary sciences.
Waltz’s structural realism attracted criticism from the start, and continues to do so today, almost twenty-five years after Theory of International Politics was published. But it is impossible not to acknowledge that it decisively shifted the terms of debate in international theory, returning realism to the mainstream, where it has remained ever since. In the 1980s, 1990s and 2000s, the field was defined by a series of arguments between the realists and their critics, as first the neo-liberal institutionalists and then various bands of constructivists, feminists, postmodernists and critical theorists lined up to attack Waltz and his students.
Without Waltz and without structural realism, we would have seen no ‘offensive’ and ‘neo-classical’ realism, no ‘agent-structure’ debate, and no ‘anarchy is what states make of it’. Whatever one thinks about his revival of realism, and about the many responses to it, it is impossible to imagine what IR would have looked like without Theory of International Politics, as well as Waltz’s many other works. For that reason alone, he will be remembered as one of the great thinkers of the field.
It is by Ian Hall in e-ir.
What would have happened in a Waltzless world? I am inclined to think that the trajectory of IR would have been similar without Waltz. There would have been the rise of economistic liberalism (rationalism), and of cultural liberalism (constructivism), institutionalism, and the various kinds of critical theory – all are found beyond IR. What would have happened to realism? Would it really have been forced out of the mainstream? I think that is quite likely since realism has been marginalized in non-American IR. If so, then Waltz saved realism.