as enlightened absolutism. Many of the major political and intellectual figures behind the American Revolution associated themselves closely with the Enlightenment: Benjamin Franklin visited Europe repeatedly and contributed actively to the scientific and political debates there and brought the newest ideas back to Philadelphia; Thomas Jefferson closely followed European ideas and later incorporated some of the ideals of the Enlightenment into the Declaration of Independence; and Madison incorporated these ideals into the U.S. Constitution during its framing in 1787. Theories of government Locke, one of the most influential Enlightenment thinkers, based his governance philosophy in social contract theory, a subject that permeated Enlightenment political thought. English philosopher Thomas Hobbes ushered in this new debate with his work Leviathan in 1651. Hobbes also developed some of the fundamentals of European liberal thought: the right of the individual, the natural equality of all men, the artificial character of the political order (which led to the later distinction between civil society and the state), the view that all legitimate political power must be "representative" and based on the consent of the people, and a liberal interpretation of law which leaves people free to do whatever the law does not explicitly forbid. Both Locke and Rousseau developed social contract theories in Two Treatises of Government and Discourse on Inequality, respectively. While quite different works, Locke, Hobbes, and Rousseau agreed that a social contract, in which the government's authority lies in the consent of the governed, is necessary for man to live in civil society. Locke defines the state of nature as a condition in which humans are rational and follow natural law, in which all men are born equal and with the right to life, liberty, and property. However, when one citizen breaks the law of nature both the transgressor and the victim enter into a state of war, from which it is virtually impossible to break free. Therefore, Locke said that individuals enter into civil society to protect their natural rights via an "unbiased judge" or common authority, such as courts. In contrast, Rousseau's conception relies on the supposition that "civil man" is corrupted, while "natural man" has no want he cannot fulfill himself. Natural man is only taken out of the state of nature when the inequality associated with private property is established. Rousseau said that people join into civil society via the social contract to achieve unity while preserving individual freedom.