Your post was very insightful and it made me think of this. Imagine an "Internet government" consisting of a voluntary international association that does some of the major functions of government: retirement insurance (aka Social Security), medical insurance (Medicare/Medicaid), and various other minor services, such as passport identification. You could voluntarily sign up for such a government and agree to accept its laws. In return, you could move freely within international boundaries and be freed from signing up for your local government's similar services, ie you wouldn't have to pay social security tax. Such a government, freed from geographical constraints, could be well-designed and modern, offering better guarantees of fiscal prudence and sound currency than any national government does. And membership would be strictly voluntary, unlike current national identities, so it would be in that sense "libertarian". Well, what a brainstorm!