The Nolan Chart is a diagram that places political ideologies on two axes, an x-axis measuring economic freedom and a y-axis measuring personal freedom. It was named after its inventor, David Nolan of the United States Libertarian Party, who first used it to explain how libertarian ideology differed from either the Republican or Democratic partisan platforms.

The Nolan Chart has two dimensions, differing from the traditional left/right distinction, the circular perception of the political spectrum, the Vosem Chart, the VALS system and other political taxonomies. In its original form, with x-axis labeled "economic freedom" and y-axis "personal freedom", a Nolan Chart resembles a square divided into four quadrants. The upper left quadrant represents liberalism — favoring government that taxes more and spends more for activities such as welfare, Social Security and funding for the arts and that encourages more barriers on trade and business regulations (which David Nolan labeled "low economic freedom"), but supporting personal choice in issues such as marijuana, homosexuality and the draft (which he labeled "high personal freedom"). At the bottom right is its converse, conservatism, whose coordinates place it as supporting high economic freedom and low personal freedom. Conservatives want lower taxes and fewer social programs but support regulation by the government of cultural issues and personal behavior. The Nolan Chart places David Nolan's own ideology, libertarianism, at the top right, corresponding with high freedom in both economic and social matters. The fourth quadrant at the bottom left represents the antithesis of libertarianism. David Nolan originally called this philosophy populism, but many later renditions of the chart have used the label authoritarianism instead.

The Nolan Chart has also been rotated and visually represented in a few other ways, such as having conservatism and populism/authoritarianism at the top and libertarianism and liberalism at the bottom. In another popular portrayal, the Nolan Chart takes a rhomboid form, with left representing liberalism, right representing conservatism, down representing authoritarianism, and up representing libertarianism.

The chart is inspiration for many political self-quizzes based on these four categories -- liberal, libertarian, conservative and populist/authoritarian -- of political thought, many of which have been written in computer code to be taken by visitors on the Internet, e.g. at http://www.self-gov.org/quiz.html.

The advocates and writers of these quizzes are most often libertarian, and a common remark by them about their tests is that people who are libertarians inside and didn't know it will discover their true political leanings. The detractors of the Nolan Chart are most often people who accuse people with libertarian beliefs of using it to further their agenda and gain converts to their party and political movement. One specific accusation is that libertarian "recruiters" try to convince people that, because they hold several libertarian positions, they must make all their beliefs libertarian in order to stay consistent with the ideology.

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