The ethnic dimension to social relations can be distinguished from dimensions based on neighbourliness, national origin, race and religion etc., but ethnic conflicts are not a special class of conflicts. The significance of a shared ethnic origin varies with the location and scale of social relations. In local communities relations are multidimensional; ties based on different attributes are balanced against one another and against individual interests. Outside the range of personal acquaintance a shared ethnic origin may be a basis on which individuals are mobilised for collective action and for bargaining with other groups, though some individuals will seek to be free-riders. Mobilisers from elsewhere may induce individuals to change their relative preference for ethnic association, destroy local methods of dispute regulation, and so polarise relations that the participants treat their relations with members of an opposed ethnic group as unidimensional. Outside institutions, including foreign governments, can help resolve ethnic conflicts by providing guarantees that facilitate ethnic bargaining.