What’s wrong with these pictures? A critique of Waltz, Walt and McFaul

Reflecting on the ideas that have been offered to explain interstate conflict, Kenneth Waltz famously identified three images of war. Waltz’s method to rule out certain causes as the underlying causes of war was to identify constant and variable variables. The fact that the variety in one variable is not matched by the variety in another variable then allowed him to question the assumed causal relationship between the two variables. But whereas in Man, the State, and War he argued that agency, because of its constancy, cannot explain variations in war and peace, in his later book Theory of International Politics he made the opposite claim that agency, because of its variety, cannot explain the constant outcome of war. The paper inquires into the reasons for this fatal but overlooked contradiction and shows how it confounds current debates over the causes of Russia’s war against Ukraine.