I've been delving some more into the Democratic Freedom Caucus and related movements. In particular I followed the links from an essay by Todd Altman and came upon his pages on neolibertarianism and geolibertarianism. I'm not sure what's so "neo" about neolibertarianism -- it seems to be standard libertarian theory along the lines of Murray Rothbard, Ludwig von Mises, and Ayn Rand -- but geolibertarianism definitely contains a bit of a twist. In particular, it absorbs quite a bit from the economic theories of Henry George (of whom I must admit to being ignorant). It seems that the Georgists make a distinction between man-made property -- that is, created wealth -- and law-made property -- that is, title to land as granted by a State (or other law-making entity). Georgists, or at least geolibertarians, seem to maintain that land titles are unnatural because they are, Altman's words, "generally used as a means of assuming exclusive possession of land without adhering to John Locke's proviso" (i.e., without ensuring that there be "enough and as good left in common for others"). Now this is a factual claim, and as such should be falsifiable. Its truth is doubtful when population is low, though it becomes more plausible as population increases. Locke's notion of "good" here also introduces some difficulties: if I discovered San Francisco Bay and claimed the area around the Presidio (as the explorer Fremont did), one could claim that I've left "enough" but not "as good" (in fact, the land Fremont claimed was confiscated by the state for military purposes). One would need an objective definition of "good" (at least applied to land) in order to clearly define the scope of the Lockean Proviso.
These reservations aside, there does seem to be some prima facie plausibility to the Georgist position that land ownership is created by the law whereas what I produce by my own labor is free of any legal shadow. Concerns over the legitimacy of land title lead geolibertarians to advocate a tax on land but not on property -- improvements such as buildings are man-made property, whereas the value of land is essentially inherent (e.g., insurance agencies usually counsel one to not insure the land value, only the improvements, since the land value is as solid as the earth). Application of Georgist principles also would lead to a repeal of all taxes on labor and on returns on capital investments.
I'm not quite convinced by the Georgist arguments, since I have my doubts that all or even most property ownership violates the Lockean Proviso. But if one must have taxes (a claim that I dispute), I suppose the "Land Value Tax" is a relatively less harmful tax than an income tax or even a sales tax.