Every age eventually faces the challenge of what in recent times has been called systemic change, what used to be called regime change or revolution. Societies and political systems exist in a tension between preservation of existing institutions and traditions, and new ways of organization, conduct, and thinking. Paradigms shift to varying degrees that range from mild reform that maintains continuity with traditional standards and life, to revolutionary change that radically breaks from them. The temptation to change in more radical and revolutionary ways is greater when the existing order is perceived as inherently flawed and unjust. The United States is grappling with such circumstances. It is struggling to determine its identity and character as a political regime and in a larger cosmological sense. One force of radical change in American politics and culture is socialism.