Rule by the people has taken many institutional forms. Democracy is a system of government in which ultimate authority rests with the citizenry, exercised directly or through elected representatives. Regular, competitive elections, civil liberties, and the rule of law are widely regarded as core features of modern democratic practice.

Ancient Athens practiced a direct form limited to free male citizens. Representative democracy expanded in the nineteenth and twentieth centuries as suffrage broadened. Waves of democratization have alternated with periods of authoritarian reversal across different regions.

Historians and political scientists debate the social conditions that sustain democracy and the threats posed by inequality, polarization, or external pressure. The ideal of popular sovereignty continues to inspire movements even where institutions fall short of the standard.

• Government based on popular authority
• Practiced directly or through representatives
• Requires elections, rights, and legal constraints
• Has expanded and contracted across history