“It comes down to a question of whether property owners have a right to deny access to their land to others, arbitrarily . . .”

No, it does not come down to that at all. I am quite happy to welcome undocumented immigrants onto my property; so what it comes down to is a question of whether or not other people, who do not own my property, have a right to deny access to my land to others, arbitrarily. Of course they do not. They have no right to do anything but keep their preferences, and their borders, on their own property, not on mine.

“This may well be true; but if so it actually renders all argument irrelevant since their right to have any policy- including open borders- unsupportable. For instance, an illegitimate state operating an open borders policy is enacting unjust domain over the properties of its citizens-”

Horsefeathers, sir. This is absurd.

Of course you are right that in my view, no nation-state can legitimately have any policy at all, because no nation-state can legitimately exist. But the mistake here is in trying to treat political demands for amnesty or open borders as if they were demands for an active policy in the first place. They are not demands for government action; they are specifically demands for a structured sort of in-action, and they cannot reasonably be described as “actions of an illegitimate State against its oppressed citizens.” They are not impositions of “unjust domain over the properties of its citizens” because the property rights of a states’ citizens don’t include the right to force immigrants off of other people’s property in the neighborhood. Nothing is being imposed upon them, any more than the absence of war is somehow the political imposition of “peace” on unwilling civilians; or, at least, if you are going to claim that a state without border restrictions “is enacting unjust domain over the properties of its citizens” in virtue of its lack of border restrictions, then you will have to tell me whose property rights are being restricted by the open borders, and how they are being restricted by government’s simple refusal to harass or detain international migrants.

Carl: Why else would there be so much disagreement? Because many people who claim to be libertarians, aren't actually libertarians, but rather believe in a toxic mix of small-government Constitutionalism and belligerently nationalist conservatism. Of course, if that's what you believe, then borders have an obvious place in your philosophy: any mini-statist is going to be in favor of some border enforcement (since territoriality and borders are essential features of the state as such, and they defend the enforcement power of states); and if you are into a lot of mind-numbingly dumb ideas about the American nation-state, then these often lead to violently dehumanizing people from other countries controlled by different nation states, and invoking a lot of mind-numbingly savage nonsense about the "right" of that nation-state to preserve its national character, etc. How they think that they can square these ideas with a professed belief in "individual liberty" or even in "limited government" is really kind of beyond me, but as long as "libertarianism" is, for many, not the creed of radical individual liberty regardless of political identity or legal status, but rather some kind of code-word for a leaner, meaner state and hyperconservative American nationalism, there will continue to be people who convince themselves that it can somehow be done. That doesn't make the question complicated. It makes their attempts to ignore or avoid the obvious consequences of libertarian principles complicated -- even downright acrobatic. But that's another kind of complication entirely. My recent post Auburn police department contact sports