This chapter discusses a political theory that has come to the fore in the IR discipline since the end of the Cold War. Understanding IR liberalism nevertheless requires acquaintance with the historical context in which the broader political arguments for freedom and toleration were first enunciated. The chapter thus provides a brief historical outline of liberalism's development before surveying some key liberal tenets and their manifestation in IR. It concludes with a discussion of some of the challenges facing contemporary IR liberalism in the current era.
Liberalism is often seen as the characteristic political philosophy of the modern West. Its central principles – freedom, (human) rights, reason, progress, toleration – and the norms of constitutionalism and democracy are deeply embedded in Western political culture. Nonetheless, liberal theories of IR were until recently disdained as utopian by IR scholars no less than by diplomats. The two World Wars and the Cold War seemed to bear out the realist thesis that the international milieu was inevitably subject to the harsh imperatives of power politics.
For a while after the Cold War, however, the world suddenly looked quite different. There was no hostile power threatening the liberal democracies, major inter-state war seemed unthinkable and the international economy was organised in accordance with the norms of the liberal market (Friedman 1999; Fukuyama 1989). The predominant school of liberal IR theory, most strongly represented in the United States, concentrated almost exclusively on this moment of liberal triumph, invoking the insights of democratic peace theory (DPT), US-led institutionalism and the transformative power of the global marketplace as intrinsic to winning the Cold War (Doyle, 1983, 1986; Friedman 1999; Fukuyama, 1989; Kegley, 1993; Keohane, 1984).
In more recent times, this scenario and its dominant theoretical explanations have come under challenge from a variety of sources. In the face of terrorist threats, the crisis in the global capitalist order after 2008, the rise in global inequality and the many problems facing contemporary democratic societies, one sees widespread scepticism concerning the analytical capacity of mainstream IR liberalism to find even adequate explanations, let alone answers, for these contemporary issues from its base in a (mainly) positivist methodology (see Sterling-Folker 2015).