Charles A. (2020) Isolationism: A History of America's Efforts to Shield Itself from the World (Oxford University Press, 2020). Wheeler, N.J. (2003) "The Humanitarian Responsibilities of Sovereignty: Explaining the Development of a New Norm of Military Intervention for Humanitarian Purposes in International Society" in Welsh, J.M. Humanitarian Intervention and International Relations Oxford: Oxford Scholarship Online, pp. 29–50. Walzer, M.J. (2000) Just and Unjust Wars New York: Basic Books, pp. 86–108. External links International law International relations theory Libertarian theory Paleolibertarianism Political theories