Can electoral institutions induce lasting changes in citizens’ voting habits? We study the long-term and spillover effects of compulsory voting in the Swiss canton of Vaud (1900–1970) and find that this intervention increases turnout in federal referendums by 30 percentage points. However, despite its magnitude, the effect disappears quickly after voting is no longer compulsory. We find minor spillover effects on related forms of political participation that also vanish immediately after compulsory voting has been abolished. Overall, these results question habit formation arguments in the context of compulsory voting.