He was referring to the term used to described Thomas Jefferson, a “classical liberal.”
Classical liberalism as the term was used during the time period of our Founding Fathers is most nearly reflected in the conservative principles of today that Rush keeps harping on: small government, stronger state sovereignty, lower taxes, more individualism, more choice, greater freedom of enterprise, all undergirt by a common morality, a common culture, and a national language, all wrapped up in a pretty bow that that we call our borders.
That, my friend, is a Libertarian.