Liberalism - what is it?

Since the Republicans claim that I am a Liberal, I wondered exactly what they meant. Somehow I feet that the discussion I might find on National Review might - let's say - "lack something in rigor," I went to the Stanford Encyclopedia of Philosophy and found this. This is the first paragraph:

Liberalism as a Political Theory

Liberty

‘By definition’, Maurice Cranston rightly pointed out, ‘a liberal is a man who believes in liberty’ (Cranston, 459). In two different ways, liberals accord liberty primacy as a political value. First, liberals have typically maintained that humans are naturally in ‘a State of perfect Freedom to order their Actions…as they think fit…without asking leave, or depending on the Will of any other Man’ (Locke, 1960 [1689]: 287). Mill too argued that ‘[T]he burden of proof is supposed to ith those who are against liberty; who contend for any restriction or prohibition…. The a priori assumption is in favour of freedom…’(Mill, 1991 [1859]: 472). This might be called the Fundamental Liberal Principle (Gaus, 1996: 162-166): freedom is normatively basic, and so the onus of justification is on those who would limit freedom. It follows from this that political authority and law must be justified, as they limit the liberty of citizens. Consequently, a central question of liberal political theory is whether political authority can be justified, and if so, how. It is for this reason that social contract theory, as developed by Thomas Hobbes (1948 [1651]), John Locke (1960 [1689]), Jean-Jacques Rousseau (1973 [1762]) and Immanuel Kant (1965 [1797]), is usually viewed as liberal even though the actual political prescriptions of, say, Hobbes and Rousseau, have distinctly illiberal features. Insofar as they take as their starting point a state of nature in which humans are free and equal, and so argue that any limitation of this freedom and equality stands in need of justification (i.e., by the social contract), the contractual tradition expresses the Fundamental Liberal Principle.

The article is lengthy and extremely informative.