Libertarians are actually closer, philosophically, to the Founding Fathers than so-called "social" conservatives.
Maybe so.
But what do you think our Founding Fathers would think of the Libertarian Party today?
Would they be impressed? Or horrified?
And vice versa.
3. freedom from control, interference, obligation, restriction, hampering conditions, etc.; power or right of doing, thinking, speaking, etc., according to choice.
1. the quality or state of being liberal, as in behavior or attitude.
Remember the classical definition of Liberalism?
2. a political or social philosophy advocating the freedom of the individual, parliamentary systems of government, nonviolent modification of political, social, or economic institutions to assure unrestricted development in all spheres of human endeavor, and governmental guarantees of individual rights and civil liberties.
Also,
a. A political theory founded on the natural goodness of humans and the autonomy of the individual and favoring civil and political liberties, government by law with the consent of the governed, and protection from arbitrary authority.
That's been supplanted by the newer definition. Ask anybody today what is a Liberal, and you'll probably get the former definition, rather than the latter. Most people (except Conservatives, of course) don't even know what a Classical Liberal is.