Libertarianism as it exists in the United States is basically a mid-20th century American philosophy, at least in origin. Owing perhaps to a combination of bad introductory classes and an urge for a longer historical pedigree, libertarians often like to pretend that great canonical thinkers prior to that time were also libertarians. But as that is an obvious anachronism, it turns out to be untrue. There are some lesser knowns here and there along the trail who might come close, but basically none of the big old philosophical names can rightly be associated with this mid-20th century libertarianism.
Previously, I pointed out John Locke’s anti-libertarian transgressions, in which he observed and prescribed a solution to the intense coercion of labor contracts made between those with very unequal bargaining strength, contracts he analogized to slavery. To suggest Locke was not a mid-20 century American libertarian was so infuriating that some rather amusing, but ultimately incompetent, push back followed.
It’s not just Locke in whom the libertarians have misplaced their admiration. Presumably because he wrote the book On Liberty (the only book of his seemingly taught in political philosophy courses), I’ve run into more libertarians than I can count who think John Stuart Mill was one of them. While Mill clearly was a fan of what we might call personal liberty, he realized economic matters were not so easily disposed of by appeals to personal liberty. In fact, in his Principles of Political Economy, Mill comes out in favor of what we would now call a market socialist system.
Here is one choice quote from Book V of Principles of Political Economy, in which Mill explains the inherently social nature of wealth distribution and economic institutions in general:
The Distribution of wealth … is a matter of human institution solely. The things once there, mankind, individually or collectively, can do with them as they like. They can place them at the disposal of whomsoever they please, and on whatever terms. Further, in the social state, in every state except total solitude, any disposal whatever of them can only take place by the consent of society, or rather of those who dispose of its active force [i.e. government]. Even what a person has produced by his individual toil, unaided by any one, he cannot keep, unless by the permission of society. Not only can society take it from him, but individuals could and would take it from him, if society only remained passive; if it did not either interfere en masse, or employ and pay people [i.e. police] for the purpose of preventing him from being disturbed in the possession. The distribution of wealth, therefore, depends on the laws and customs of society. The rules by which it is determined are what the opinions and feelings of the ruling portion of the community make them, and are very different in different ages and countries; and might still be more different, if mankind so chose.
For Mill, who gets what is a social decision. The only thing that causes anyone to ever have entitlement over pieces of the world are the laws and institutions of society. It is police violence in concert with legal rules that actually demarcate what belongs to whom, and there is no demanded-by-the-universe way of orienting those institutions. Also, it's clear that curtailments of liberty are at the very heart of all economic institutions, laissez-faire ones just as much as socialist ones.
Sadly, there is no real mainstream liberal discourse in favor of this obviously correct view. When the most radical sentiment coming from the liberal mainstream is Elizabeth Warren pointing out that some high-income folks ignore the extent to which public investment is a factor in the production that generates their high incomes, it is no real mystery why, in this intellectual vacuum, previously discredited theories of property rights maximalism (discredited in the sense that they are clearly liberty-infringing) seem to some like a smart philosophical move.