Social scientists often attribute the absence or moderation of ethnic conflict, in ethnically diverse societies, to the presence of cross-cutting cleavages - that is, to dimensions of identity or interest along which members of the same ethnic group may have diverse allegiances. Yet estimating the casual effects of cross-cutting cleavages is difficult. The authors develop an experimental research design to examine why ethnicity appears to have little political salience in Mali, an ethnically heterogenous sub-Saharan African country where ethnic identity is a poor predictor of vote choice and parties do not form along ethnic lines. They argue that the cross-cutting ties afforded by an informal institution called cousinage can help explain the weak association between ethnicity and individual vote choice. Ethnic and cousinage ties between voters and politicians both enhance the credibility of politicians' policy promises, yet neither dimension of identity becomes dominant as a basis for vote choice due to their cross-cutting nature.