Social Mobility and Stability of Democracy: Reevaluating De Tocqueville*
用动态政治经济学模型检验托克维尔关于社会流动性巩固民主的论点，发现高流动性反而可能削弱民主稳定性，因为中位选民预期向上或向下流动时会倾向限制其他群体的政治权利。
An influential thesis often associated with de Tocqueville views social mobility as a bulwark of democracy: when members of a social group expect to join the ranks of other social groups in the near future, they should have less reason to exclude these other groups from the political process. In this article, we investigate this hypothesis using a dynamic model of political economy. As well as formalizing this argument, our model demonstrates its limits, elucidating a robust theoretical force making democracy less stable in societies with high social mobility: when the median voter expects to move up (respectively down), she would prefer to give less voice to poorer (respectively richer) social groups. Our theoretical analysis shows that in the presence of social mobility, the political preferences of an individual depend on the potentially conflicting preferences of her “future selves, ” and that the evolution of institutions is determined through the implicit interaction between occupants of the same social niche at different points in time.