How did the world come to be organized into sovereign states? Daniel Philpott argues that two
historical revolutions in ideas are responsible. First the Protestant Reformation ended
medieval Christendom and brought a system of sovereign states in Europe culminating at the
Peace of Westphalia in 1648. Second ideas of equality and colonial nationalism brought a
sweeping end to colonial empires around 1960 spreading the sovereign states system to the rest
of the globe. In both cases revolutions in ideas about legitimate political authority
profoundly altered the constitution that establishes basic authority in the international
system. Ideas exercised influence first by shaping popular identities then by exercising
social power upon the elites who could bring about new international constitutions. Swaths of
early modern Europeans for instance arrived at Protestant beliefs then fought against the
temporal powers of the Church on behalf of the sovereignty of secular princes who could
overthrow the formidable remains of a unified medieval Christendom. In the second revolution
colonial nationalists domestic opponents of empire and rival superpowers pressured European
cabinets to relinquish their colonies in the name of equality and nationalism resulting in a
global system of sovereign states. Bringing new theoretical and historical depth to the study
of international relations Philpott demonstrates that while shifts in military economic and
other forms of material power cannot be overlooked only ideas can explain how the world came
to be organized into a system of sovereign states.
