“Most libertarians don’t tend to have any problems with open borders and if they do it is mostly because we have a welfare state. Other than that they don’t see any problem.”
That is, they are only looking at one facet – the economic facet of voluntary exchange.
However, libertarianism, especially anarcho-libertarianism, also requires a community of consistent understanding of natural law, or at least libertarian principles. Any specific libertarian society’s legal code, even if that community has multiple competing protection agencies and courts, the legal code will have particularized expressions/understandings of what the libertarian principles entail. That is, as the great David Gordon mentioned, they will be worked out through convention.
A “common law” will develop and the precise details of this could and would vary from libertarian community to another. The common law system of governance in Somali anarchism is different from that of Irish anarchism will be different from North American anarchism. David Gordon mentioned in one of his recent Mises lectures that any given libertarian community will require a common understanding of the law and common conventions in interpreting and applying the principles of libertarianism.
Which is to say, Hoppe is rather correct on this point. People from different cultures will – and it is completely acceptable for them to do so – have different means of governing even under libertarian principles and a libertarian society will have to maintain itself by not having absolutely open borders. Free trade and free exchange, but not absolutely free entry for permanent residency and membership. Joining the community would thus be subject to certain stipulations including to agree to accept the rules/legal conventions as worked out in that particular libertarian society rather than insisting upon the ones from one’s own community (“multicultiralism” in the strong, leftist sense; – something that is not possible anyhow).
Libertarian communities cannot be “neutral among conceptions of the good” anymore than progressive-statist liberalism can be, in practice. Though it can be tolerant of a certain amount of exceptions living among them (say an 80-20 rule; that is to say, 80% cohesion, 80% of people essentially agreeing within any particular libertarian community/society, with 20% being “resident aliens,” metics, holding whatever outlandish beliefs they may want to hold – including a perverse belief in welfare-statism progressivism).
This is not to say a libertarian community will have to be a mind control state insisting upon conformity of belief and conformity of opinion; – it is just to say that if there is wide disagreement, it will break down. Then one will get the “bad” (prototypically-understood) anarchism, the sort of anarchism that is the popular definition of anarchism (Beirut in the ’80s “anarchism”), with factions fighting because they hold widely differing conceptions and beliefs.
Thus, as I have said before; – and so far this is my fullest (but still badly put) expression of why this is – to the extent to which libertarians (including the otherwise great Bob Murphy) have supported “open borders” in the now, under the current welfare-state-multiculturalism system, they have taken themselves out back behind the barn and shot themselves in the back of the head.
They have guaranteed the exact opposite of what they might want.
The only way, the absolute only way, however slim the chance would be, to achieve their goals is to get a libertarian system in place first, and then invite anyone who wants to share in it and who pledges to adopt and accept the same understanding/conventions in how it will be governed to join it, but reject anyone who refuses to live under the same understanding (such people can found their own libertarian society/community, however large or small, and put in place their own particular understanding and their own particular conventions, and likewise invite others to join it) – something like the “Utopia” in Nozick’s “Anarchy, State, and Utopia” (his much-neglected last chapter). [Take one obvious but non-ethnic/cultural example: I wish Left-Libertarians all the best, I hope it works out for them, but I myself have no interest in living in a economic Left-Libertarian community while, even though I’m a minarchist – mostly for pessimistic reasons – I would love to live in a economically Right/Paeleo-libertarian community.]
But the problem with libertarians on this score is they focus on one aspect of things here, the economic aspect, and on the “freedom of association” aspect, in a society (any modern Western society) that does not actually allow “freedom of association” (which includes the right not to associate). So, as a compromise for my above, I would suggest that they fight for, and put in place, true freedom of association before insisting upon “open borders.” But they know that will be folly, futile, they will not get that under the current dispensation; the only thing they will get is harangued for being “closet racists” (which they are not) who want to “return to Jim Crow and Sundown Towns,” (which they do not).
Which again illustrates that while they understand this reality, but continue to push for “open borders” on the grounds of “I should be free to associate with whomever i want, it’s my right – plus it is economically advantageous,” they are doing nothing more than slitting their own ideological throats and lending weight to statists who want nothing more than to reduce liberty to a political nullity. Great job, thanks for playing, better luck next millennium in some other civilization.