Chapter 5 turns to an examination of the ties between working-class representatives and constituents, by taking an in-depth look at the relationship between labor unions, political parties, and workers in Argentina and Mexico. We show that the evolution of unions and parties throughout history lead to working-class deputies in Argentina having stronger ties to workers and a better track record of policy representation than working-class deputies in Mexico. Then we leverage an original dataset of working-class representation over time and across states in Argentina and Mexico to show empirically that whereas increases in working-class representation in Argentina are associated with citizens evaluating their representative institutions more positively, the increased presence of working-class legislators in Mexico leads to backlash and more negative evaluations of legislatures and political parties.