The objective of this Article is to integrate legal and social conceptions of citizenship as they materialize at the geographic, political, and social border crossings that accompany transnational mobility. Rather than pose the question "who is the citizen?," I ask "who is the citizen’s Other?," partly as a means of surfacing what we mean by citizenship by thinking about who we designate as its alterity. Against the current of most contemporary scholarship, I commend resurrecting the concept of statelessness as an antipodal reference point for citizenship. My intuition is that a version of statelessness still dwells in the substratum of much citizenship discourse, and that rendering a plausible account of it under contemporary conditions may prove helpful in linking conversations about legal and social citizenship. I supplement the conventional understanding of the stateless person (apatride) as one who lacks any citizenship in a state by also designating as stateless one who possesses citizenship but lacks a state. My analysis draws on Hannah Arendt’s famous exegesis on the relationship between the apatride, the refugee, and the condition of rightlessness, as well as contemporary refugee jurisprudence. I demonstrate how subject positions commonly identified as the citizen’s Other, including the refugee, the alien and the second-class citizen, are better understood as nested within a larger matrix where the apatride represents the ultimate negation of citizenship. I then introduce the notion of the "heft" of citizenship as a method of assessing how legal citizenship and social citizenship interact to position an array of subjects between these stylized poles of citizenship and statelessness.