J. David Singer

Nations at war: Case study: Iran/Iraq War (1980)

Introduction The onset of the Iran/Iraq War (1980) is explained on the basis of empirical uniformities established by systematic quantitative analyses. As Hempel (1966:68) notes, scientific explanations of individual events may be provided through inductive subsumption under probabilistic laws, as well as through deductive subsumption under universal laws. The following inductive explanation demonstrates that the case of the Iran/Iraq War is a specific instance of a set of patterns which have appeared in a much larger number of cases. The Iran/Iraq War of 1980 conforms to a set of probabilistic laws based on empirical regularities identified at the dyadic level of analysis. These two states: shared a common border (contiguity); had nondemocratic regimes (absence of joint democracies); were economically underdeveloped (absence of joint advanced economies); and exhibited an unstable military balance (a capability shift in 1979 and a transition in 1980). Add to this the classification of the dyad as an “enduring rivalry” (based on the frequency of previous militarized conflicts) and the existence of an unresolved territorial dispute (over the Shatt alArab waterway), and the occurrence of dyadic war with initiation by the militarily superior challenger of the status quo (Iraq) was a high-probability event consistent with a broad array of empirical war patterns. Although the nonoccurrence of the event is not precluded logically due to the inductive form of argument, nevertheless the war may be considered “explained” by its subsumption under probabilistic laws.