"Yet that’s precisely why Paul’s 1.0 argument breaks down on its own terms: at the scene of a four-century crime against humanity — the kidnap, torture, enslavement, and legal oppression of African-Americans — ideal theory fails. We libertarians, never burdened with an excess of governing power, have always had a utopian streak, a penchant for imagining what rich organic order would bubble up from the choices of free and equal citizens governed by a lean state enforcing a few simple rules. We tend to envision societies that, if not perfect, are at least consistently libertarian.
Unfortunately, history happened. Rules for utopia can deal with individual crimes — the mugger and the killer and the vandal — but they stumble in the face of societywide injustice. They tell us the state shouldn’t sanction the brutal enslavement or humiliating legal subordination of a people; they have less to say about what to do once we have. They tell us to respect the sanctity of the property rights that would arise as free people tamed the wilderness in John Locke’s state of nature. They have less to say about the sanctity of property built on generations of slave sweat and blood."
Why Rand Paul Is Right ... and Wrong | Cato Institute