The PhD thesis studies the impact of cleavages on electoral choice in Switzerland. This is done in three different research perspectives. In a first longitudinal part, the development of the salient Swiss cleavages (religion, social class, rural-urban and language) is examined from 1971 until the national elections in 2011. The second, contextual perspective analyses the current impact of cleavages in more detail. Besides the impact of both individual and contextual factors separately, interaction effects between the individual and the environment are examined. In a final part of the thesis, both research perspectives are combined to see whether the impact of cleavages has harmonised across contexts (cantons) over time.