¹ Some of the ideas presented here are developed in more detail in Mathias Risse and Michael Blake, “Migration, Territoriality, and Culture,” in Jesper Ryberg, Thomas Petersen, and Clark Wolf, eds., New Waves in Applied Ethics(Aldershot, UK: Ashgate Publishers, 2007); as well as in Michael Blake and Mathias Risse, “Is There a Human Right to Free Movement? Immigration and Original Ownership of the Earth” (forthcoming; available as Kennedy School of Government Faculty Research Working Paper Series RWP06-012).

² See, for instance, Mathias Risse, “What to Say about the State,” Social Theory and Practice 32, no. 4 (2006), pp. 671–98.

³ But Blake and Risse do pursue these questions. See Blake and Risse, “Is There a Human Right to Free Movement?”