Libertarianism is a political philosophy that holds individual liberty as the primary political value, generally favoring strict limits on the scope and power of government and an expansive scope for personal, civil, and economic freedoms. The term is used to describe a range of positions, from minimal-state views that permit government only in narrow functions such as defense and the courts, to anarchist views that reject the state altogether. Because the term covers this range, its precise boundaries are contested; see libertarianism-definition-viewpoint-debate.

In the United States, libertarianism is often associated with a fusion of free-market economics and social permissiveness - support for deregulation, low taxation, and limited government spending alongside opposition to government restriction of personal conduct such as drug use, sexual behavior, and speech. Libertarian ideas have influenced multiple political movements and parties, including the libertarian-party-united-states, factions within the Republican Party, and the Tea Party Movement, though these groups differ in emphasis and in how consistently they apply libertarian principles across economic and social domains.

Contemporary libertarian thought spans several overlapping traditions, including classical liberalism, Austrian School economics, objectivism, anarcho-capitalism, and minarchism. These traditions share a general preference for voluntary exchange and private property over state coercion, but disagree on questions such as the proper size of government, the legitimacy of taxation, immigration policy, and the role of intellectual property. On immigration specifically, libertarians divide between open-borders positions grounded in freedom of movement and restrictionist positions grounded in concerns about welfare-state strain or cultural cohesion; see libertarianism-immigration-debate. Libertarian-leaning positions appear across the political spectrum; some self-described libertarians align primarily with the political right on economic issues and with the political left on social and civil-liberties issues, while others resist a left-right framing entirely. The relationship between libertarianism and contemporary American conservatism is itself debated, with some viewing libertarianism as a strand within the broader conservative coalition and others viewing it as a distinct tradition. See libertarianism-conservatism-relationship-debate.

A longer account of libertarianism's intellectual origins and development is available at libertarianism-history.

• Minarchism - Holds that government should be limited to a small set of core functions, typically national defense, police, and courts, with most other functions left to private or voluntary arrangements.
• Anarcho-capitalism - Holds that all functions of government, including defense and law enforcement, can and should be provided through voluntary, market-based arrangements rather than a state.
• Classical liberal viewpoint - Emphasizes individual rights, rule of law, and limited but not absent government, drawing on Enlightenment-era liberal thought.
• Paleolibertarian viewpoint - Combines libertarian economic positions with socially traditionalist or conservative cultural views, often skeptical of cultural liberalism.
• Left-libertarian viewpoint - Combines support for personal and civil liberties with skepticism of concentrated private economic power, sometimes favoring redistribution or critiques of property norms uncommon among other libertarian viewpoints.
• Critical viewpoint - Argues that libertarian proposals underestimate the role of government in providing public goods, correcting market failures, or addressing structural inequality, and that minimal-state or stateless arrangements would produce worse outcomes for many people.

• Koch network influence controversy - Dispute over the extent to which libertarian think tanks, advocacy organizations, and political campaigns have been shaped by funding from Charles Koch and related donor networks.
• Confederacy and states'-rights controversy - Dispute over whether certain self-described libertarian or states'-rights arguments, historically and in some contemporary usage, have served to justify or downplay slavery and segregation.

• libertarianism-history
• libertarianism-definition-viewpoint-debate
• libertarianism-conservatism-relationship-debate
• libertarianism-immigration-debate
• libertarian-party-united-states
• Republican Party
• Tea Party Movement
• United States of America — Conservative American Viewpoint

1. Boaz, David. *The Libertarian Mind: A Manifesto for Freedom*. New York: Simon & Schuster, 2015.
2. Nozick, Robert. *Anarchy, State, and Utopia*. New York: Basic Books, 1974.
3. Friedman, Milton, and Rose Friedman. *Free to Choose: A Personal Statement*. New York: Harcourt, 1980.
4. Zwolinski, Matt, and John Tomasi. *The Individualists: Radicals, Reactionaries, and the Struggle for the Soul of Libertarianism*. Princeton: Princeton University Press, 2023.
5. MacLean, Nancy. *Democracy in Chains: The Deep History of the Radical Right's Stealth Plan for America*. New York: Viking, 2017.