Charles de Montesquieu was a French, Enlightenment-era philosopher who greatly influenced the Constitutional Framers and the nature of the Constitution itself. In his The Spirit of the Laws, Montesquieu advocated for the separation of power into three branches of government, in order to prevent a democracy from descending into an autocracy or a monarchy.

The Social Contract is a series of essays, written by Jean Jacques-Rousseau in the eighteenth century. Its primary argument is that only the people have the absolute right to govern, and a leader can only assume this right if agreed upon by a majority of the people. Rousseau’s writings were very influential for the Constitutional Framers.

According to statism, the rights of the individual are secondary to the rights and protection of the nation as a whole. Although the supreme right of the individual is supposed to be an established and guaranteed theory behind the formation of American politics and government, statism has taken on increased importance in recent years.

The Leviathan was written by Thomas Hobbes in the seventeenth century. It can be seen as the philosophical foil for John Locke’s Two Treatises on Government. In The Leviathan, Hobbes argue that human beings are naturally belligerent and inclined toward aggressive competition and self-interest. He believed that, due to the defects of human nature, the best form of government was an absolute ruler, who could constrain the chaos that would ultimately ensue in a free and democratic society.

Montesquieu was a French Enlightenment-Era philosopher whose writings greatly influenced the Founding Fathers. Most notably he argued determinedly for a separation of powers in any democratic government to ensure that no one part of the government could become despotic.

Laissez-faire economics is a system of economic practice where the market is entirely free and completely devoid of government interference. It long had an ideological impact on the formation of the American economy, but is very far removed from the type of economy that America has at the present.

John Locke was an English Enlightenment-Era philosopher who famously wrote two treatises on government. His beliefs that there were certain inalienable rights granted to all individuals—to life, liberty, and property—were very influential over many of the American Founding Fathers. In particular, Thomas Jefferson based many of his writings and political opinions on John Locke’s philosophies, as can be seen, for example, in his own writing that all men have the right to "life, liberty, and the pursuit of happiness."

The Social Contract states that the only legitimate right to govern comes from a mandate of the people. It was written by Jean-Jacques Rousseau and greatly influenced the American Founding Fathers.

John Locke is often considered the grandfather of the American constitution. His ideas on natural rights of life, liberty, and property and limited government are ideas that inspired the Founders. Other philosophers in the question came later, and were not specifically tied to early constitutional framers.

John Locke wrote that man was endowed with the natural rights of life, liberty, and property. Thomas Jefferson changed it to Pursuit of Happiness when he wrote the Declaration of Independence.