Political ideologies in the United States

American political ideologies conventionally align with the left–right political spectrum, with most Americans identifying as conservative, liberal, or moderate. Contemporary American conservatism includes social conservatism, classical liberalism and economic liberalism. The former ideology developed as a response to communism and the civil rights movement, while the latter two ideologies developed as a response to the New Deal. Contemporary American liberalism includes progressivism, welfare capitalism and social liberalism, developing during the Progressive Era and the Great Depression. Besides modern conservatism and liberalism, the United States has a notable libertarian movement, developing during the mid-20th century as a revival of classical liberalism. Historical political movements in the United States have been shaped by ideologies as varied as republicanism, populism, separatism, fascism, socialism, monarchism, and nationalism.

Political ideology in the United States began with the country's formation during the American Revolution, when republicanism challenged the preexisting monarchism that had defined the colonial governments. After the formation of an independent federal government, republicanism split into new ideologies, including classical republicanism, Jeffersonian democracy, and Jacksonian democracy. In the years preceding the American Civil War, abolitionism and secessionism became prominent. Progressivism developed at the beginning of the 20th century, evolving into modern liberalism over the following decades, while modern conservatism developed in response. The Cold War popularized anti-communism and neoconservatism among conservatives, while the civil rights movement popularized support for racial justice among liberals. Populist movements grew in the early-21st century, including social democracy and Trumpism.

Americans of different demographic groups are likely to hold different political beliefs. Men, white Americans, the elderly, Christians, and people without college degrees are more likely to be conservative, while women, African Americans, young adults, non-Christians, and people with college degrees are more likely to be liberal. Conservatism and liberalism in the United States are different from conservatism and liberalism in other parts of the world, and ideology in the United States is defined by individualism rather than collectivism.