The non-citizen is the new ?other?. From popular discourse to political pronouncements and academic research, the non-citizen has become one of the subjects du jour. Among the ranks of the non-citizen, one finds a lesser-known category of people which has yet to be considered seriously by liberal political theory ? the stateless. Thus far, liberal political theory has either ignored this category of persons or subsumed them under the subjects of immigration or refugeehood. The present article challenges this theoretical exclusion (...) in two ways. First, it analyses the treatment of statelessness within the works of three prominent theorists on just membership ? Michael Walzer, Seyla Benhabib and William Barbieri, Jr ? and contends that these authors ignore the stateless as a unique category of non-citizen. Secondly, it explains why statelessness demands a distinct theoretical framework than is currently provided for within liberal political theory. The article contends that just membership questions necessitate not simply looking at who is let in and what naturalization procedures should be extended to them, but also entails examining who has always been on the inside and to whom we need to justify their continued exclusion. (shrink)