One common explanation for ethnicized politics and limited national identification in Africa lies with colonial boundaries. Europeans frequently divided ethnic groups as they divvied territory in the nineteenth century; this might have long-run repercussions, as individuals prioritize ties with coethnics in neighboring states rather than with non-coethnic co-nationals. Contra these expectations, we argue that divided groups
should have weaker attachments to their ethnicity than non-divided groups will, because partition particularly disrupted pre-existing traditional institutions of governance and exchange within these groups. We argue that partition weakened traditional authorities and, consequently, ethnic identities through three mechanisms: (1) administrative shifts that reduced traditional authorities’ power; (2) limitations on leaders’ capacity to raise revenues; and (3) exacerbating intra-group divisions among co-ethnics living on different sides of the borders. We test this using georeferenced data from rounds 3-6 of the Afrobarometer and find support for our argument. These results are robust to different measures of the extent to which an ethnic group was split and various considerations of ethnic groups’ local and national demographic and political power. Our findings have important implications for studies of the legacies of colonialism and identity politics in Africa today.