Population Shifts and Civil War: A Test of Power Transition Theory

Do shifts in the distribution of ethnic group populations within a multinational state make civil war more likely? This article tests the proposition that they do using the competing logic of two core theories of interstate politics: power transition (PTT) and balance of power theory (BPT). The universe of potential population transition types are reduced to nine, and the logic of each of the competing explanations of war likelihood are reduced to four testable hypotheses. Overall, PTT fares better than BPT; although the article concludes that, as is the case at the interstate level, the key determinate of war likelihood rests more with how power is perceived than with raw changes in its distribution across the spectrum of meaningful political actors. Finally, the article offers a useful framework for further specifying the conditions under which population shifts alter the likelihood of an escalation to civil war.