Does the introduction of proportionality in electoral systems help to boost popular evaluations of democracy? This article takes advantage of an electoral reform in Lesotho to conduct a natural experiment. We trace shifts over time in popular political support, using Afrobarometer data collected before and after reform to measure mass satisfaction with democracy and public trust in political institutions. We find both direct and indirect effects. In the aggregate, Lesotho's transition from a majoritarian to a mixed electoral system is directly associated with increased levels of citizen support for the country's state and regime. Importantly, however, formal institutions have only indirect effects at the individual level, where a person's informal partisan status – as a member of a winning majority or losing minority – mediates the impacts of institutional change.