Despite extensive research on voting, there is little evidence connecting turnout to tangible outcomes. Would election results and public policy be different if everyone voted? The adoption of compulsory voting in Australia provides a rare opportunity to address this question. First, I collect two novel data sources to assess the extent of turnout inequality in Australia before compulsory voting. Overwhelmingly, wealthy citizens voted more than their working-class counterparts. Next, exploiting the differential adoption of compulsory voting across states, I find that the policy increased voter turnout by 24 percentage points which in turn increased the vote shares and seat shares of the Labor Party by 7–10 percentage points. Finally, comparing across OECD countries, I find that Australia's adoption of compulsory voting significantly increased turnout and pension spending at the national level. Results suggest that democracies with voluntary voting do not represent the preferences of all citizens. Instead, increased voter turnout can dramatically alter election outcomes and resulting public policies.