Protests can engender significant institutional change. Can protests also continue to shape a nation's contemporary politics outside of more formalized channels? I argue that social movements can not only beget institutional change, but also long‐run, attitudinal change. Using the case of the U.S. civil rights movement, I develop a theory in which protests can shift attitudes and these attitudes can persist. Data from over 150,000 survey respondents provide evidence consistent with the theory. Whites from counties that experienced historical civil rights protests are more likely to identify as Democrats and support affirmative action, and less likely to harbor racial resentment against blacks. These individual‐level results are politically meaningful—counties that experienced civil rights protests are associated with greater Democratic Party vote shares even today. This study highlights how social movements can have persistent impacts on a nation's politics.