Disputed meanings of the term
Some try to restrict the term classical liberalism so as to stop in the nineteenth century or so. Libertarians argue that there is no interruption, no massive rejection of the past and no fork in the classical liberal tradition - only a single uninterrupted tradition, the only one which does lay claim to such theorists as Locke, Hume, Smith, Jasay and Bastiat, as opposed to Hobbes, Rousseau, Proudhon and Marx.
Similarly, some split classical liberalism into a political liberalism and an economic liberalism, so as to be able to consider liberal justifications of democracy independently from liberal justifications of capitalism. But libertarian thinkers themselves claim that this is missing the point, because the classical liberal tradition is neither political nor economical: it is a theory of Law - of what is or isn't legitimate for people to do.