The authors present a theory of the general enabling conditions for war which predicts that war is possible, though not inevitable, when the conditions of the theory are satisfied. Whether a war will actually occur depends upon the idiosyncratic situational factors that are outside the scope of the theory. Three conditions make war possible: (i) Aspirations do not match achievements: governments only initiate wars when their achieved share of global capabilities differs from their aspired share of capabilities. (2) Salience: governments only initiate wars against other governments when there is a history of substantial interaction. (3) Power: governments never initiate wars against other governments that have a substantially greater military capacity. These conditions may be viewed as a series of three filters that identify pairs of countries between which war is possible. The theory predicts that wars will not occur in any dyad that does not pass through all the filters. In testing this theory for all nations between 1816 and 1980, the authors allowed for the fact that governments may preemptively initiate wars against other governments that meet these conditions.

The argument of this paper is that the emergence of military dictatorships, such as the Brazilian regime of 1964, is not caused by an economic crisis of dependent capitalist development. Rather, it results from a polarization and radicalization of the democratic regime by which it is preceded. Democracies handed down from above, like that in Brazil and other South American democracies, lend themselves to polarization and radicalization. They therefore favor the emergence of modern forms of autocracy.

Soviet military decision making is characterized by a division of labor between the party, which issues broad policy guidance, and the professional military, which oversees the development of the armed forces based on that guidance. There is to date no civilian institution whose functions parallel those of the General Staff. The party is now, and has historically been, dependent on the professional military for the formation of options on strategy, organization, and force composition. The Soviets have never equated civilian control and authority with civilian management. Absolute party authority over defense policy has been maintained through control of personnel and resource allocation.

The preventive motivation for war arises from political leaders' perceptions that their states' military power and potential are declining relative to those of a rising adversary, and from their fear of the consequences of that decline. It is conceptualized as an intervening variable between changing power differentials and the outbreak of war, and is distinguished from preemption and other sources of better-now-than-later logic. The strength of the preventive motivation is hypothesized to be a function of a state's expectations regarding its rate of military decline, the margin of its inferiority in the future, the probability of a future war, and the probability of a victorious war now with acceptable costs. It is also affected by the risk orientation of decision makers; the influence of the military in the political process; and domestic political factors that undermine the political security of decision makers as well as the military power and potential of the state.

Since its inception, the Correlates of War project has been in the forefront of the quantitative analysis of war. This review seeks to integrate some of the major findings of the project into an explanation that identifies the steps that regularly occur before war. The explanation must be seen as an artificial construct, based on inductive generalizations from existing evidence and clues, whose primary utility at this stage of inquiry is to see what patterns precede wars, what conditions are associated with peace, and what factors may be of causal significance. The findings and the explanation derived from them are relevant to assessing some common realist practices and policies of states such as alliance making, military build-ups, hard-line bargaining, balancing of power, peace-through-strength, and deterrence. It is argued that among equals, power-politics behavior does not avoid war, but leads political actors to take steps that bring them closer to war.