Keywords: Kenneth Waltz, International Relations theory, realism, structuralism, foreign policy.
Two claims about the nature and scope of theories in International Relations can be found in Kenneth Waltz's work. The first claim is that it is possible to develop a theory of international politics, i.e. a theory that is capable to predict the outcomes of interactions among states without necessarily predicting their foreign policy behaviour. The second claim is that it is possible to develop a structural theory of politics, i.e. a theory that rigorously separates structural and unit-level causes and only considers the former. This note argues the following: (i) the two claims are distinct; (ii) Waltz does not separate them consistently; (iii) he defends the first claim by using arguments that support the second claim; (iv) the first claim is not plausible; (iv) the second claim is plausible, but it needs to be qualified.