International Relations. A self-Study Guide to Theory

parts and by the principle of the arrangement. Each unit’s behavior is differ-
ent and they produce distinct interactional outcomes when differently ar-
ranged or positioned in the system. 
To make the concept easier to grasp and to understand the concept of 
structure as applied to international politics, Waltz illustrates his definition by 
describing domestic political structures. He asks three questions about a po-
litical system in order to define its structure:
Defining political structures 
•
Ordering principle: How are the units arranged in the system? 
•
Differentiation of units and functions: What functions do the formally 
differentiated units perform? 
•
Distribution of capabilities: How is power distributed across the units? 

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Domestic political structures, or a national political system, are hierarchically 
ordered and centralized; hierarchy is the ordering principle. The units (insti-
tutions and agencies within the state) stand in relations of super- and subordi-
nation to each other. Political actors within the state are formally differentiat-
ed by the degree of their authority and the functions they perform (actors re-
sponsible for jurisdiction, legislation, bureaucratic actors, etc.). There is a 
specific distribution of capabilities (power) across the units of a national po-
litical system. Because political structures shape political processes, we can 
expect different political processes according to different structures in a na-
tional political system. For example, with regard to the type of political sys-
tem, structures in autocratic or democratic systems will differ from each oth-
er, as will those in presidential and parliamentary democracies. The behavior 
of the units (the actors in the political system) and the outcomes of their in-
teraction will be different depending on the structural features of the system. 
In international politics, the ordering principle is different. Anarchy, not 
hierarchy, is the ordering principle of the international system. International 
systems are decentralized and anarchic. There are no formal relations of su-
per-or subordination, but rather an absence of agents with system-wide au-
thority. In place of relations of super-and subordination in the international 
system, we can only find coordination of formally equal units. The units of 
the international system, the states, are not differentiated by the functions 
they perform. There is no “division of labor” in the international system. All 
states have to fulfill the same tasks regardless of the type of political system: 
ensuring survival in a self-help-system. Anarchy therefore implies the 
“sameness” of the units in the international system (Waltz 1979: 93). In con-
trast to a national political system, the criterion of functional differentiation is 
not needed to define the structure of the international system. States are “like 
units“, meaning that all states are alike in being an autonomous political unit, 
a sovereign state or sovereign political entity. Only if the organizing principle 
changes (that is, from anarchy to hierarchy) a functional differentiation might 
be possible. 
However, states differ according to their capabilities (power). States have 
greater or lesser capabilities for performing similar tasks. Capabilities/power 
are attributes of units. In contrast, for Waltz, the distribution of capabilities 
is not: In neorealist theory, the distribution of capabilities across units be-
comes a defining criterion for the structure of the system. Here the notion of 
the “positional picture” becomes clearer: states in the system are placed or 
positioned by their power. Depending on how power is distributed in the in-
ternational system, we can think of multipolar, bipolar or unipolar interna-
tional systems. This definition enables a distinction between international po-

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litical systems according to the number of great powers and how they are po-
sitioned.
The structure of a system changes with variations in the distribution of 
capabilities across the units. Changes in structure alter expectations about 
how the units of the system will behave and about the outcomes their interac-
tions will produce (Waltz 1979: 101).