For the most part, the noncitizenship presented in this book is latent, but actions both of States and of individuals can activate it, making an individual both vulnerable and challenging to a State and the State system. There is something faintly idiosyncratic in presenting activated noncitizenship as a relationship of both vulnerability and challenge. While one makes the noncitizen seem weak, the other emphasises the noncitizen’s power. This tension is important to understanding the relationship. Non-acknowledgement of a noncitizen’s relationship with a State including heightening the deprivations associated with noncitizenship, increasing both the individual’s vulnerability and the challenge that her/is situation poses to that State including to its legitimacy. The activation of noncitizenship, then, has two related components: a special sort of vulnerability and a special sort of challenge. Both of these operate bidirectionally: the individual is vulnerable/challenging to a State built upon liberal democratic principles and the State system; and such a State and State system are vulnerable/challenging to the individual. Vulnerability and challenge are not unique to noncitizenship, but in this relationship they take a special form and are deepened in special ways.