International Relations. A self-Study Guide to Theory

Part II: 
Theories of International Relations: 
Five Approaches

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123 
5.
Neorealist theory 
Learning steps 
Introduction ......................................................................................................... 
124 
Step 1: 
Background and core question ................................................................... 
125 
Step 2: 
Assumptions about actors and structures ................................................. 
127 
Step 3: 
The neorealist explanation of international politics .............................. 
129 
3.1. 
Level of analysis ..................................................................................... 
129 
3.2. 
The neorealist concept of structure ........................................................ 
130 
3.3. 
Structures as causes ................................................................................ 
133 
3.4. 
Balance of power politics ....................................................................... 
134 
3.5. 
Peace and stability in the international system ....................................... 
136 
Step 4: 
Check your understanding: 
key aspects and review questions ............................................................... 
137 
Step 5: 
Final self-study and consolidation .............................................................. 
138 

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124 
Introduction 
This unit marks the beginning of Part II, which covers five theories of IR. At 
the core of this unit will be neorealist theory as developed by Kenneth Waltz in 
his Theory of International Politics (1979). By discussing neorealist theory’s 
core assumptions and explanatory model in detail, we will learn about the par-
ticular perspective of international politics that neorealist theory provides. 
When learning about theoretical approaches to International Relations, 
there are several reasons to start with neorealist theory.
Within the academic discipline of International Relations, neorealist theo-
ry – developed continuously by Kenneth Waltz beginning in the 1950s and 
completely worked out in his book “Theory of International Politics” (1979) 
– is the first “scientific” theoretical approach to IR. It was Waltz’s objective 
to construct a general theory of IR which could explain the way all of interna-
tional politics functions. At the heart of neorealism lies a strong belief that 
general, legal-like knowledge about international politics is possible. Within 
IR, Waltz was the first scholar to build his theoretical argument on the 
grounds of clearly demarked assumptions about actors and structures in in-
ternational politics. 
Neorealist theory is also the most parsimonious, or least complex, theory 
of International Relations. This alone makes it easy to start with. However, 
even more important than being the first “scientific” theoretical approach, the 
position neorealism holds within the academic discipline of IR almost neces-
sitates beginning theoretical studies with neorealism. As you will learn, al-
most all theoretical approaches draw on neorealism as a point of reference 
against which to sharpen their own theoretical arguments. 
In terms of “intellectual traditions”, realism is the oldest “theory” of in-
ternational politics. Please be aware that we are now talking about realism as 
a theoretical strand of IR. It should not be confused with realism as a philos-
ophy of science (as discussed in Part 1 of the book). Realism as realist think-