In Hume's Enquiry Concerning the Principles of Morals, he includes a discussion of justice. In some ways, it's a discussion to thrill the heart of any modern libertarian; Hume writes as if the right to property was pretty much the only right people have, and his rules concerning acquisition and transfer of property rights were pretty much those later given by Nozick (and earlier given by Locke, of course). It was, of course, not Hume's intention to be original, and no doubt the brevity of his discussion of the rights in question resulted from his awareness of how thoroughly they'd been covered elsewhere.
However, while Hume was no doubt a believer in the strong property rights he defended (in some respects he was politically quite conservative; he even defended monarchy, after all), in interesting respects his discussion was quite subversive. Hume insisted that the right to property is not a natural right (he insisted that there were no natural rights whatever, of course), and so that the rules of justice in the distribution of property were only justified on the basis of their usefulness. This being the case, he was fully aware that principles justified by usefulness could be overridden when it was useful to override them. Thus, his account has no difficulty explaining such exceptions as there have to be to the basic rules (taxes to pay the enforcers of the rules, for instance), while the likes of Locke and Nozick have to invoke fanciful notions of implicit consent to government authority to justify any exceptions to their absolutist rules.
Of course, while it isn't their first line of defense, libertarian types will turn to consequentialist arguments when pressed (Hume notes the tendency of pretty much everyone to do this, and naturally cites it as evidence that we're all consequentialists deep down). Often, their arguments will rely on the suggestion that immutable facts of human nature guarantee that socialism could never work, and capitalism is the only realistic system. In general, conservatives seem to like the idea of immutable human natures.
Hume says some interesting things which strike me as relevant to that, too, though. In addition to admitting in favor of the cause of the levelers the obvious moral arguments, Hume admits that socialism sometimes works. He cites examples of close families, newly formed cults, the Spartan Equals, and ancient agrarian laws.* However, he considers these to be exceptional cases. Indeed, they do not demonstrate the usefulness of socialism generally, but it seems to me that they are probably sufficient to blunt the "immutable nature" arguments. If it truly were immutable nature, the exceptions, the cases of socialism working well, should not be rare; instead, they should not exist at all. Given the frequency with which the libertarian crowd insists on appealing to immutable human nature, I think it's a notable fact that the argument has this problem.
* Agrarian laws are a particularly fascinating case. Hume does not cite which examples he is thinking of, but Adam Smith would later contrast government policies which encouraged small land holdings (British colonies in the Americas) with government policies that encouraged vast estates (Spanish colonies in the Americas), and note that the latter were economically much less productive. Policies favoring the large land-holders were of course preferred by the Spaniards in order to maintain an aristocratic class, the same effect such policies had in Rome, where agrarian reform was never very successful (Hume cites it as having succeeded in some Greek cities; he was perfectly aware the Romans didn't manage to do much to put it in practice). In Rome, they contributed greatly to tension between the aristocracy and the lower classes and the decay and collapse of the democratic elements of the Republic, and eventually the Republic itself. In modern times, poor countries with aggressive agrarian reform policies in the mid 20th century are disproportionately represented among the counties which successfully became less poor and more democratic by the late 20th century.
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