The Rise of Liberalism
It was toward the end of the Renaissance that the political philosophy of "Classical Liberalism" (from liber, the Latin word for freedom) began to develop. Starting with the publication of Leviathan by Thomas Hobbes in 1651, a number of writers began to examine the premises of government and the assumptions of human nature upon which those premises were based. It was these writers, expanding upon the beliefs of the Greeks and Romans, who first began to actually enunciate and write down the belief in the equality of human beings and individualism.
At the time they were writing, government was still seen as a gift of God, with a ruler's legitimacy drawn from the Divine Right of Kings. Royalty was higher born and was somehow superior in the eyes of God, and so should rule over those who were lesser born. For this reason a king was not answerable to those he ruled, but only to God; there could be no legitimate reason for challenging the will of government, because that would also challenge the authority of God.
The liberal philosophers rejected the "divine right of kings" and the idea that some people were higher born in the eyes of God. Instead they realized that all people were born equal in his eyes. They saw government not as a gift of God, but rather a creation of man. Government was a contract entered into by self-willed individuals in an attempt to increase their chances of achieving satisfaction. Each person agreed to give up absolute personal freedom, such as the freedom to do harm or steal, so that he or she might enjoy even greater freedom to pursue and achieve happiness. In the Classical Liberal philosophy, government was a tool to extend the individual's freedom.
This rational reason for government, extending freedom, became a standard by which to judge rulers. No longer were they answerable only to God; now they were answerable to the people they ruled. These philosophers had laid the groundwork for the rebirth of democracy in Europe. With the King's right to govern no longer emanating from heaven, Europe slowly began to shift from monarchal to representative forms of government. The equality of man provided the justification; since all men were created equal, and hence had the equal ability to choose what was best for themselves, they had the a right to chose their government.
But these philosophers realized that government often poses a danger to individual freedom. They saw that government has a great tendency to assume responsibility for people, even when people wanted to be responsible for themselves. So to insure freedom, they recognized the need to place limits on the power of the government.
The philosophers of Classical Liberalism are the true root of our government. Our Founding Fathers were attempting to codify the belief in individual freedom and responsibility. The government they designed was to be a tool to extend freedom of the individual.
Our Founders also made allowances for the dangers of government. Practical experience with King George and his bureaucracy had reinforced the idea that it was government itself which most often oppressed the people and denied individual freedom, and so they took care to have the government do only what was absolutely necessary. Instead of concentrating all power in the hands of a king or parliament, they divided the power among three branches - the Executive, the Legislative and the Judicial - with a system of checks and balances to keep too much power and the potential for abuse from accumulating in any one of them. The Bill of Rights is a further effort to guard against the encroachment of government, a clearly defined list of powers over the individual that the government must never possess. The Founders didn't trust government with any significant degree of control over the individual; they realized the best way to insure individual choice was for government to have as little control over people as possible. The Constitution, along with the Bill of Rights, is the crowning achievement of Individualist Liberalism, the practical embodiment of its philosophy and ideas.