This volume is designed to provide an explanation of war in international politics grounded on data-based, empirical research. The study is organized around research findings at the analytic levels of the state, dyad, region, and international system. Because wars follow from political decisions, two basic decisionmaking models – the rational and the nonrational – are examined in relation to the explanatory framework of the volume. In addition, case analyses of two wars – Iran/Iraq (1980) and World War I (1914) – are provided as demonstrations of scientifically-based explanations of historical events. The primary factors responsible for the onset and seriousness of both wars are identified and the explanations are developed according to the scientific model of “covering laws.” The Conclusion presents a discussion of the potential for probabilistic predictions of conflict within the context of war and peace studies.

Principal among the objectives of this book is an effort to generate a series of probabilistic laws drawn from consistent empirical regularities at multiple analytic levels. Such probabilistic laws may then be subsumed within theories that explain the underlying processes of the empirical uniformities. Wars in the two case studies – Iran/Iraq (1980) and World War I (1914) – are explained logically by inductive probability given the empirical regularities (probabilistic laws) derived from the data-based research. In other words, the two case-study wars are explained by inductive subsumption under laws of probabilistic form. We view such explanations as intrinsic both to scientific inquiry and to the development of empirically grounded theory.