This leads, secondly, to Waltziantheory. Structural realism undoubtedly reshaped
the whole field after its first elaboration. Structural realism/neorealism – the terms
are used interchangeably^12 – became the magnetic north by which students of
relations between states navigated their different journeys to explanation and
understanding. All theories of international politics had to have a theory about
structural realism, if not of it.
It will be helpful here, in this introductory chapter, to give the briefest synopsis
of the theory’s chief elements, before they are unpacked and examined in detail in
subsequent chapters – from the inside (for example by John Mearsheimer), from the
outside (for example by Andrew Linklater), and from inside/outside (for example
by Georg Sørensen). In brief, the theory of structural realism explains the inter-
national system in relation to a dominant structure (anarchy) defined by the interplay
between its component units (states seeking survival) which are characterised by
particular distributions of power (the capabilities of the units). Crucially, for Waltz,
his is a (‘systemic’) theory of international politics, not a (‘reductive’) theory of
the units. The theory therefore explains the ‘causal weight’ of the system, not the
differing political cultures and other factors that shape the foreign policies and other
interactions of the units. Waltz set out to produce a ‘parsimonious’ theory. In this
regard – and against those wanting the theory to deliver much more than it could
- Waltz has said with great clarity that his theory sought to explain as opposed to
accurately reflect reality (‘A theory, though related to the world about which
explanations are wanted, always remains distinct from that world’).^13 He has also
consistently insisted that his theory does not explain everything in international let
alone world politics (in his words: ‘Not everything need go into one book and not
everything can go into one theory’).^14
The agenda set by structural realism, however parsimonious the theory, raises
rich questions. These include: debates over key concepts such as ‘structure’ (see
Nicholas Onuf’s chapter); methodological debates over theory (see Wæver’s dis-
cussion of theory’s theory) and gender (see Elshtain’s discussion of where and
whether it comes in); political/theoretical puzzles over power transitions (see the
chapter by Richard Ned Lebow and Benjamin Valentino), power balancing (see the
chapter by Conny Beyer); the implications of changes in statehood (see the chapter
bySørensen), the tensions between anarchy and hierarchy (see the chapter by Ian
Clark), and different approaches to understanding continuity and change (note the
Process Sociology perspective in the chapter by Linklater, and the World History
perspective advanced by Barry Buzan and Richard Little). These are just a start. One
could add debates on ‘relative’ versus ‘absolute’ gains, ‘defensive’ versus ‘offensive’
realism, the meanings of the ‘stag hunt’, and so on; and, of course, lurking in all
these discussions, are issues relating to the ostensible idealist–materialist binary (note
the chapters by Onuf and Beyer). As a result of contributing to this huge agenda, it
is difficult to imagine today’s academic International Politics in the absence of the
work of Waltz: if he had never existed, we would have to have invented him.
Third, what of Waltz as a theorist? Without doubt, Waltz set new standards of
rigour in his attempt to theorise the state system (on his place in realism’s
Realism redux 5