Twenty-first-century efforts to address an "immigration state of emergency" are anchored by timeworn racialized and gendered discourses of national precariousness and belonging. Through an assessment of recent policies governing mixed-citizenship-status families, this article studies how rhetorics of protecting the security of a vulnerable national citizenry justify the disparate legal treatment of undocumented migrants and their US citizen children. Part 1 of the article explores how recent attempts to repeal birthright citizenship for US-born children of undocumented parents merely reflect in exaggerated form how procedures for determining foreign-born children's citizenship have long relied upon racialized and feminized discourses of national vulnerability. Part 2 examines how family-deportation regimes forcing undocumented parents to choose between deporting their citizen children with them or leaving them in state custodial institutions like foster care communicate that nationalist cultural assimilation should trump the constitutional right to family and national residency. Children's unique developmental needs combine with national security fears to authorize sociolegal states of emergency. By evaluating 2010-13 immigration enforcement legislation, the channeling of children from mixed-legal-status families into foster care, and new policies like prosecutorial discretion and Deferred Action for Childhood Arrivals, the article contributes to the feminist, ethnic, and migration studies literatures.