This paper proposes an integrated simple theory of bargaining and conflict between ethnic groups, delivering novel predictions on secessionist versus centrist conflict, and confronting them to the data. We find that greater size of the opposition ethnic groups reduces the likelihood of peaceful union with respect to secessionist and centrist conflict, and that cultural preference similarity decreases the risk of secessionist conflict with respect to centrist conflict and with respect to union. Finally, we show that greater patience increases the likelihood of secessionist conflict with respect to centrist conflict.