The introduction has identified the perceived incompatibility between liberal thought and green concerns and the origins of the green critique that has sought to further explore this incongruity with reference to Rawls’s unrivalled contribution to liberalism in the second half of the twentieth century. Rawls has clearly come to be seen as a figurehead for liberal thought, and so it would seem that his theory is taken to be a legitimation – and even a post-hoc explanation – of how liberal societies operate in both theory and practice. Yet this link, that his theory represents an extended apologia for liberalism, and indeed potentially for the epoch of modernity itself, becomes more tenuous if it can be shown that there is a real tension between his argument for liberal principles of justice (an equal scheme of liberties for all, and the equality of opportunity) and the conservative implications of his intergenerational ‘wellordered society’, which emerges once green concerns are introduced. As such, this chapter seeks to highlight the central, perennial question that has dogged theories of political liberalism since the European Reformations of the sixteenth and seventeenth centuries; namely, how can first principles of justice, capable of motivating citizens towards unity, be found in societies that are characterized by a deep-rooted, yet reasonable, plurality of comprehensive and doctrinal visions of the good life? Given that this is the question Rawls’s mature political thought sought to answer, it is necessary to explain in greater detail the significance of his move from a partially comprehensive Kantian liberalism to a much more limited notion of political liberalism. It will then be possible to not only investigate how the ‘separation argument’ manifests itself in his heuristic ‘original position’, but to again highlight the uneasy relationship between a classical liberal commitment to the inviolability of individual liberties and the more conservative idea of citizens as stewards of the well-ordered society that is central to his mature works on political liberalism. We are thus faced with the question as to what room there is left for green concerns given the importance of the separation argument to Rawls’s notion of ‘justice as fairness’.