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We examine how one's adult political participation is affected by having social ties to a politician during adolescence. Specifically, we estimate the long-term effect of having had a classmate during upper secondary school whose parent was running for office on future voter turnout and the likelihood of running for and winning political office. We use unique Swedish population-wide administrative data and find that students in school classes with a larger number of politically active parents are more politically active as adults, both in terms of voting and political candidacy. Our results suggest that the effect of vertical social ties is predominantly mediated by indirect links between the politician and the student via the children of politicians. Moreover, we show that the strength of these mobilizing effects depends on the individual's basic predisposition to engage in different types of political activities.