Conventional wisdom suggests that cultural differences make conflict more likely. Culture can unite and divide, but there exists little agreement among scholars over how identity forms among states, what distinctions are most salient, and when conflict is more likely. Researchers have tended to ‘confirm’ the role of identity in an ex post facto fashion, looking only at actual conflicts with cultural differences, without considering the opportunities for conflict among groups. We address a series of problems with existing conceptions of identity and ethnicity. We distinguish between shared and different culture by religion, language, and ethnicity. Rather than equating states with just the dominant groups, we also consider how relations inv...