Democratic theory suggests that political participation shapes democratic values and instills notions of citizenship. But studies to date have focused predominantly on the act of voting, to the exclusion of other forms of participation. Those that look beyond voting focus on participation that includes deliberation (juries) or decision-making (participatory budgeting). Do other forms of civic participation have the same effects? Answering this question is challenging because the choice to participate confounds our ability to identify causal effects. I therefore turn to a unique natural experiment in Peru. Prior to every election, Peruvian officials randomly select citizens to serve as poll workers (miembros de mesa) on Election Day. Following the January 2020 congressional elections, I conducted a two-wave panel survey of these randomly selected poll workers and also randomly selected alternates. Comparing these two groups allows me to identify the causal effect of this civic participation on political attitudes. I find that civic participation increases support for and trust in democratic institutions, especially elections. I also find that it increases political efficacy and engagement. But I find suggestive evidence that these effects are conditioned by the degree to which the poll monitor had a positive experience. Civic participation does foster democratic attitudes, as long as that participation reflects well on the political system.