Effective states rely on cooperative citizens. To foster reciprocity among citizens and the state, I argue, social policy can be key. Using administrative data on civilian bureaucrats in former East Germany, I show that women giving birth after introduction of extended maternity leave saw a surge in membership of the ruling party compared to women giving birth shortly before. Beyond the direct impact, I find evidence of two-way intergenerational effects: first, affected grandmothers were more likely to become members, but not grandfathers. Second, in present-day surveys, likely affected children lean more towards left-wing ideology, in particular female survey respondents.