The Ideological Peace

How does ideology impact international politics? Scholars have highlighted the role of ideological preferences about the appropriate process of policymaking, especially democracy versus nondemocracy. However, we argue that beliefs about the appropriate outcome of policymaking are also highly germane. People view foreign countries that share their individual left-wing or right-wing ideology as being less threatening, and are less supportive of sanctions and the use of force against them. We term this dynamic the “left/right peace.” These two faces of ideology are additive. Observers in democratic countries are especially disinclined to engage in conflict if a foreign state is aligned on both ideological dimensions, which we term the “ideological peace.” Four survey experiments in two countries and an analysis of militarized interstate disputes provide strong evidence for our argument. Our theory significantly contributes to debates about whether politics stops at the water’s edge and the impact of polarization on political violence.