The broad expansion of non-electoral political participation is considered one of the major changes in the nature of democratic citizenship in the 21st century. Most scholars but also governments, transnational and subnational political institutions, and various foundations have adopted the notion that contemporary democratic societies need a more politically active citizenry. Yet, contemporary democracies widely differ in the extent to which their citizens get involved in politics beyond voting. Why is political activism other than voting flourishing in the United States, but is less...