It is almost a cliché to argue that while European governments favour a world order based on international law and organisation, Americans see international society as an epiphenomenon of American power. Robert Kagan (2003: 3) famously captured this when, at the height of the Iraq War controversy, he wrote that ‘Americans are from Mars and the Europeans are from Venus’. Where the latter were ‘realising Immanuel Kant's “perpetual peace”’, the former was ‘mired in history, exercising power in an anarchic Hobbesian world where international law and rules are unreliable, and where true security and the defense and promotion of a liberal order still depend on the possession and use of military might’. Chastened by what America found (or did not find) in Iraq, Kagan seemingly stepped back from some of the implications of this analysis. The USA, he concluded, could not and should not ignore the question of legitimacy and the role that law played in providing that. The USA must realise, moreover, that it could not claim legitimacy by acting unilaterally in its self-interest and without reference to the greater good (Kagan 2004). Yet even after recognising this, Kagan argued, the two continents would remain politically divided. That schism might not reflect the Hobbesian–Kantian divide as implied in his earlier work.