The political implications of population aging for democratic systems are fundamental. Questions of democratic legitimacy are raised as the political equilibrium between the generations is upended. Drawing on evidence from liberal democracies with a focus on Japan, the democracy with the oldest electorate, we identify and analyze three demographic effects on the political system: participation effects deriving from younger voters’ marginalization among the electorate; representation effects demonstrated by the dominance of elderly lawmakers inside the parliament and government; and policy effects manifesting in a preference for policies catering to an aging majority. By breaking down these key effects and contextualizing them in broader debates of political demography, we call attention to the normative repercussions of the interplay between demography and democracy and make a case for enhanced generational pluralism.