Liberalism, the belief in freedom, equality, democracy and human rights, is historically associated with thinkers such as John Locke and Montesquieu, and with constitutionally limiting the power of the monarch, affirming parliamentary supremacy, passing the Bill of Rights and establishing the principle of "consent of the governed". The 1776 Declaration of Independence of the United States founded the nascent republic on liberal principles without the encumbrance of hereditary aristocracy—the declaration stated that "all men are created equal and endowed by their creator with certain unalienable rights, among these life, liberty, and the pursuit of happiness"."The Constitution of the United States" (PDF). A few years later, the French Revolution overthrew the hereditary aristocracy, with the slogan "liberty, equality, fraternity" and was the first state in history to grant universal male suffrage. The Declaration of the Rights of Man and of the Citizen, first codified in 1789 in France, is a foundational document of both liberalism and human rights, itself based on the U.S. Declaration of Independence. The intellectual progress of the Enlightenment, which questioned old traditions about societies and governments, eventually coalesced into powerful revolutionary movements that toppled what the French called the Ancien Régime, the belief in absolute monarchy and established religion, especially in Europe, Latin America and North America.

William Henry of Orange in the Glorious Revolution, Thomas Jefferson in the American Revolution and Lafayette in the French Revolution used liberal philosophy to justify the armed overthrow of what they saw as tyrannical rule. The 19th century saw liberal governments established in nations across Europe, South America and North America. In this period, the dominant ideological opponent of classical liberalism was conservatism, but liberalism later survived major ideological challenges from new opponents, such as fascism and communism. Liberal government often adopted the economic beliefs espoused by Adam Smith, John Stuart Mill and others, which broadly emphasized the importance of free markets and laissez-faire governance, with a minimum of interference in trade.

During 19th and early 20th century in the Ottoman Empire and Middle East, liberalism influenced periods of reform such as the Tanzimat and Nahda and the rise of secularism, constitutionalism and nationalism. These changes, along with other factors, helped to create a sense of crisis within Islam which continues to this day—this led to Islamic revivalism. During the 20th century, liberal ideas spread even further as liberal democracies found themselves on the winning side in both world wars. In Europe and North America, the establishment of social liberalism (often called simply "liberalism" in the United States) became a key component in the expansion of the welfare state.Arthur M. Schlesinger Jr. "Liberalism in America: A Note for Europeans" (1956). The Politics of Hope (Boston: Riverside Press, 1962). "Liberalism in the U.S. usage has little in common with the word as used in the politics of any other country, save possibly Britain". Today, liberal parties continue to wield power, control and influence throughout the world, but it still has challenges to overcome in Latin America, Africa and Asia. Later waves of modern liberal thought and struggle were strongly influenced by the need to expand civil rights.Worell, p. 470. Liberals have advocated for gender equality, marriage equality and racial equality and a global social movement for civil rights in the 20th century achieved several objectives towards those goals.

Early history

Isolated strands of liberal thought had existed in Eastern philosophy since the Chinese Spring and Autumn periodRothbard, Murray (2005). Excerpt from "Concepts of the Role of Intellectuals in Social Change Toward Laissez Faire", The Journal of Libertarian Studies, Vol. IX, No. 2 (Fall 1990) at mises.org and Western philosophy since the Ancient Greeks, but the first major signs of liberal politics emerged in modern times. The economist Murray Rothbard claimed that Chinese Taoist philosopher Laozi was the first libertarian, likening Laozi's ideas on government to Friedrich Hayek's theory of spontaneous order.Rothbard, Murray (2005). "The Ancient Chinese Libertarian Tradition", Mises Daily, (5 December 2005) (original source unknown) at mises.org Many of the liberal concepts of Locke were foreshadowed in the radical ideas that were freely aired at the time. The pamphleteer Richard Overton wrote: "To every Individuall in nature, is given an individual property by nature, not to be invaded or usurped by any...; no man hath power over my rights and liberties, and I over no mans". These ideas were first unified as a distinct ideology by the English philosopher John Locke, generally regarded as the father of modern liberalism.Delaney, p. 18.Godwin et al., p. 12. Locke developed the radical notion that government acquires consent from the governed, which has to be constantly present for a government to remain legitimate.Copleston, pp. 39–41. His influential Two Treatises (1690), the foundational text of liberal ideology, outlined his major ideas.Locke, p. 170. His insistence that lawful government did not have a supernatural basis was a sharp break from previous theories of governance.Forster, p. 219.Zvesper, p. 93. Locke also defined the concept of the separation of church and state.Feldman, Noah (2005). Divided by God. Farrar, Straus and Giroux, p. 29. "It took John Locke to translate the demand for liberty of conscience into a systematic argument for distinguishing the realm of government from the realm of religion". Based on the social contract principle, Locke argued that there was a natural right to the liberty of conscience, which he argued must therefore remain protected from any government authority.Feldman, Noah (2005). Divided by God. Farrar, Straus and Giroux, p. 29. He also formulated a general defence for religious toleration in his Letter Concerning Toleration.McGrath, Alister. 1998. Historical Theology, An Introduction to the History of Christian Thought. Oxford: Blackwell Publishers. pp. 214–215. Locke was influenced by the liberal ideas of John Milton, who was a staunch advocate of freedom in all its forms.

Milton argued for disestablishment as the only effective way of achieving broad toleration.Hunter, William Bridges. A Milton Encyclopedia, Volume 8 (East Brunswick, N.J.: Associated University Presses, 1980). pp. 71–72. . In his Areopagitica, Milton provided one of the first arguments for the importance of freedom of speech—"the liberty to know, to utter, and to argue freely according to conscience, above all liberties". Algernon Sidney was second only to John Locke in his influence on liberal political thought in eighteenth-century Britain and Colonial America, and was widely read and quoted by the Whig opposition during the Glorious Revolution. Sidney's argument that "free men always have the right to resist tyrannical government" was widely quoted by the Patriots at the time of American Revolutionary War and Thomas Jefferson considered Sidney to have been one of the two primary sources for the Founding Fathers' view of liberty. Sidney believed that absolute monarchy was a great political evil and his major work, Discourses Concerning Government, was written during the Exclusion Crisis, as a response to Robert Filmer's Patriarcha, a defence of divine right monarchy. Sidney firmly rejected Filmer's reactionary principles and argued that the subjects of the monarch were entitled by right to share in the government through advice and counsel.

Glorious Revolution

Isolated strands of liberal thought that had existed in Western philosophy since the Ancient Greeks began to coalesce at the time of the English Civil War. Disputes between the Parliament and King Charles I over political supremacy sparked a massive civil war in the 1640s, which culminated in Charles' execution and the establishment of a Republic. In particular, the Levellers, a radical political movement of the period, published their manifesto Agreement of the People which advocated popular sovereignty, an extended voting suffrage, religious tolerance and equality before the law. The impact of liberal ideas steadily increased during the 17th century in England, culminating in the Glorious Revolution of 1688, which enshrined parliamentary sovereignty and the right of revolution, and led to the establishment of what many consider the first modern, liberal state. Significant legislative milestones in this period included the Habeas Corpus Act 1679, which strengthened the convention that forbade detention lacking sufficient cause or evidence. The Bill of Rights formally established the supremacy of the law and of parliament over the monarch and laid down basic rights for all Englishmen. The bill made royal interference with the law and with elections to parliament illegal, made the agreement of parliament necessary for the implementation of any new taxes and outlawed the maintenance of a standing army during peacetime without parliament's consent. The right to petition the monarch was granted to everyone and "cruel and unusual punishments" were made illegal under all circumstances. This was followed a year later with the Act of Toleration, which drew its ideological content from John Locke's four letters advocating religious toleration. The Act allowed freedom of worship to Nonconformists who refused to pledge oaths of Allegiance and Supremacy to the Anglican Church. In 1695, the Commons refused to renew the Licensing of the Press Act 1662,Professor Lyman Ray Patterson, "Copyright and 'The Exclusive Right' Of Authors" Journal of Intellectual Property, Vol. 1, No. 1 Fall 1993. leading to a continuous period of unprecedented freedom of the press.

Age of Enlightenment

The development of liberalism continued throughout the 18th century with the burgeoning Enlightenment ideals of the era. This was a period of profound intellectual vitality that questioned old traditions and influenced several European monarchies throughout the 18th century. In contrast to England, the French experience in the 18th century was characterised by the perpetuation of feudal payments and rights and absolutism. Ideas that challenged the status quo were often harshly repressed. Most of the philosophes of the French Enlightenment were progressive in the liberal sense and advocated the reform of the French system of government along more constitutional and liberal lines. The American Enlightenment is a period of intellectual ferment in the thirteen American colonies in the period 1714–1818, which led to the American Revolution and the creation of the American Republic. Influenced by the 18th-century European Enlightenment and its own native American Philosophy, the American Enlightenment applied scientific reasoning to politics, science and religion, promoted religious tolerance, and restored literature, the arts, and music as important disciplines and professions worthy of study in colleges.

A prominent example of a monarch who took the Enlightenment project seriously was Joseph II of Austria, who ruled from 1780 to 1790 and implemented a wide array of radical reforms, such as the complete abolition of serfdom, the imposition of equal taxation policies between the aristocracy and the peasantry, the institution of religious toleration, including equal civil rights for Jews and the suppression of Catholic religious authority throughout his empire, creating a more secular nation.Colton and Palmer, p. 333. Besides the Enlightenment, a rising tide of industrialization and urbanization in Western Europe during the 18th century also contributed to the growth of liberal society by spurring commercial and entrepreneurial activity.