Explaining rivalry escalation to war: Space, position, and contiguity in the major power subsystem

Vasquez's (1996) rivalry escalation theory stressed territorial disputes as the principal focus for a two-path explanation of war. Neighbors fight ove r adjacent space and non-neighbors sometimes join ongoing wars between neig hbors. But major powers are also much concerned with positional issues. Exp anding the war motivation focus to encompass both spatial and positional is sues facilitates the development of a new, more elaborate theory from which several new hypotheses can be derived, in addition to the older ones. Test ing of the new theory can also proceed with rivalry data not based on dispu te density measures, different types of contiguity can be assessed, and the presence of spatial-positional issues can be measured directly, as opposed to relying on a proximity proxy. The empirical outcome strongly supports t he two-path, two-issue theory. In the major power subsystem, noncontiguous rivals outnumber contiguous rivals, dyadic wars are scarce, and war joining has been the norm. Spatial issues alone would have a hard time accounting for this pattern. Variable mixes of spatial and positional issues are able to account for it and a number of derived hypotheses reasonably well. This is not the last word on rivalry escalation to war but it appears to be an a dditional step in the right direction.