In The Law of Peoples John Rawls argues for an international community led by a society of liberal democracies committed to spreading peace and just governance. In doing so, he builds on Immanuel Kant’s Perpetual Peace, which argued for a similar “League of Peace” to lead other nations. Both Kant and Rawls argue for disarmament and pacifism on the part of their leading nations. In this thesis, I take issue with Rawls’s pacifism, arguing that the liberal society faces threats from terrorism and humanitarian disasters abroad that could compromise their political aims to an extent that necessitates a forceful response. Working from this premise, I examine the history of philosophy of what constitutes a legitimate use of force. Using a theory of legitimacy couched in Jürgen Habermas’s discourse ethics I argue that the liberal states are able to legitimately use force abroad. Furthermore, since the legitimating process relies on a commitment to discourse, non-liberal states are precluded from taking similar actions. Finally, I address objections and in so doing argue that while liberal states may legitimately defend their political goals, they must combine such actions with robust aid and assistance abroad and rigorous oversight domestically to avoid reliance on force
