 This entry will, first, outline the historical development of ideas of world government, as well as objections to it, through a selective discussion of the idea’s history in Western political thought. The entry will focus on Dante’s medieval treatise on the necessity of a world monarch or emperor, and then consider mainly arguments by Hobbes, Rousseau and Kant that reveal more skepticism about world government as a solution to the problem of war and peace among sovereign states. The historical background section will continue with the revival of ideas of world government in the nineteenth and twentieth centuries, prompted by imperial and colonial activity, technological developments, economic globalization, and the experience of two devastating world wars. While debates about world government during the Cold War were pervaded by the ideological division of the world, the section concludes with a discussion of the acceleration of neoliberal globalization, following the end of the Cold War, as well as resistance to it, on the prospects, promise, and perils of world state formation.