A 'popular libertarianism' might ... feel all that needs to be done to bring the world to justice is to institute the minimal state now, starting as it were from present holdings. On this view, then, libertarianism starts tomorrow, and we take the present possession of property for granted.
There is, of course, something very problematic about this attitude. Part of the libertarian position involves treating property rights as natural rights, and so as being as important as anything can be. On the libertarian view, the fact that an injustice is old, and, perhaps, difficult to prove, does not make it any less of an injustice. Nozick, to his credit, appreciates this, and implies that in all cases we should try to work out what would have happened had the injustice not taken place. If the present state of affairs does not correspond to this hypothetical description, then it should be made to correspond.