Bringing critical race theory and settler colonial theory to bear on legal mobilization scholarship, this article examines the ongoing campaign to strike down the 1978 Indian Child Welfare Act (ICWA). ICWA sought to end the forced removal of American Indian children from their tribes. If successful, the challenges to ICWA’s constitutionality stand to undermine tribal sovereignty writ large. Drawing on a content analysis of documents from 17 major court cases (2013–2023) and a unique dataset of public-facing documents from the leading ICWA challengers, I interrogate the argumentative architecture of this legal mobilization. I find that the campaign to strike down ICWA is structured around three ideological maneuvers: erasure, settler normativity, and reclassification. These maneuvers scaffold a fourth – colorblindness – and the claim that ICWA is an unconstitutional race-based statute. I show how ICWA adversaries use these ideological maneuvers to legitimate white possession of Indigenous children and delegitimize tribal sovereignty. While existing work tends to treat colorblind racism and settler colonialism as analytically distinct, these findings shed light on the linkages between the two. They also marshal empirical analysis to illustrate how the embeddedness of settler colonialism and racism in the law enables broad claims to and defense of whiteness as property.