It can certainly be argued that Thomas Paine did more than anyone to promote the spirit of equality o which all modern democracy is based. Paine retorted in his Rights of Man to the English Whig, Edmund Burke's contention that each person separagely lacks the power of enforcing his natural rights. So, he, therefore deposits this right in to
common stock of society, and takes the arm of society, of which he is a part, in preference and in addition to his own. Society grants him nothing.
Paine contended that Burke's point that people forfeit their natural rights, in order to achieve civil rights, with society holding dominion over the individual was wrong; he argued that "every civil right grows out of a natural right." For Paine, human equality was a simple given. His aim in writing The Rights of Man was to promote equality in practice, by responding to Burke's
vituperative attack on the French Revolution by justifying the principles of modern republican governments. (enotes)
Paine's work is an example of eighteenth century positivism, contending that humankind can reach its full potential under republican governments that let people live free lives. Today, as people fear that governments are moving away from being republics, concerns for personal rights and freedoms are becoming prevalent.
There can be several lines of logic in answering this question. I would say that to a great extent, individuals are concerned with ensuring that civil liberties are protected. In the last three or four years, the outrage to aspects of the Patriot Act, passed in the wake of the September 11 attacks, reflected the reemergence of the protection of civil liberties. In a larger sense, Americans are concerned with the encroachment of the government into the realm of the private. The current health care debate reflects this, as opponents of government funded health care point to the idea that such an initiative will take away from individual choice and personal preference. They suggest that this reality reflects a central authority encroachment idea that many of the Framers' feared, albeit in a different context.
I would say that the historical basis for civil liberties was the thinking of people from the Enlightenment. Some important figures in this sort of thought were Jean-Jacques Rousseau and John Locke. These men said that the point of government was to protect the rights of people and that people had these rights by the fact that they were human. To many, these rights included what we now call civil liberties.
In my opinion, we are more concerned than the founders with civil liberties. We, for example, allow pornography under the umbrella of free speech, which I doubt they would have allowed. We allow all sorts of bad things to be said about the government in a way that John Adams and the Federalists did not like -- they were the ones who passed the Sedition Acts to prevent anti-government speech.