On the Margins of Citizenship provides a comprehensive, sociological history of the fight for civil rights for people with intellectual disabilities. Allison Carey, who has been active in disability advocacy and politics her entire life, draws upon a broad range of historical and legal documents as well as the literature of citizenship studies to develop a "relational practice" approach to the issues of intellectual disability and civil rights. She examines how and why parents, self-advocates, and professionals have fought for different visions of rights for this population throughout the twentieth century and how things have changed over that time.

Carey addresses the segregation of people with intellectual disabilities in schools and institutions along with the controversies over forced sterilization, eugenics, marriage and procreation, and protection from the death penalty. She chronicles the rise of the parents' movement and the influence of the Kennedy family, as well as current debates that were generated by the impact of the Americans with Disabilities Act passed in 1990.

Presenting the shifting constitutional and legal restrictions for this marginalized group, Carey argues that policies tend to sustain an ambiguity that simultaneously promises rights yet also allows their retraction.