[Demidog]

The system you describe is state ownership of all unclaimed land;

No it isn't. It's state authority over all unclaimed land within its borders. It can settle disputes and it can determine the accepted method for making claims on land.

And it can tell anyone who hasn't gone through those accepted methods to go away.

[annalex]

But the only thing we have naturally is a set of potential individual claimants; they don't come divided into foreign and domestic claimants. Under natural law, if the potential claimants agree on the process of claiming unclaimed (individually unclaimed) property, then any claim that follows the process is just. Exxon is a potential claimant and should participate in the formulation of the rules.

You make the government, which some but not all of the potential claimants commission, a necessary player in property distribution. That is wrong philosophically, -- because we can easily imagine an ungoverned society which has property rights, -- and it is surely illibertarian. Now, let us recall what the argument is about. You say that Peikoff deviates from the libertarian philosophy and I say he doesn't. If your point is that the government is a necessary element in any system of property rights, then you are debating the core libertarian principle of minimal government; but you are already wrong on whether Peikoff's views are in conformance with libertarianism.