The politics of affirmative action are currently structured as a litigious conflict among elites taking polarized stances. Opponents call for colorblindness, and defenders champion diversity. How can marginalized activists subvert the dominant terms of legal debate? To what extent can they establish their legitimacy? This paper advances legal mobilization theory by analytically foregrounding the field of contention and the relational production of meaning among social movement organizations. The case for study is two landmark United States Supreme Court cases that contested the University of Michigan’s race-conscious admissions policies. Using ethnographic data, the paper analyzes BAMN, an activist organization, and its reception by other affirmative action supporters. BAMN had a marginalized allied-outsider status in the legal cases, as it made a radical civil rights claim for a moderate, elite-supported policy: that affirmative action corrects systemic racial discrimination. BAMN activists pursued their agenda by passionately defending and, at once, critiquing the university’s policies. However, the organization’s militancy remained a liability among university leaders, who prioritized the consistency of their diversity claims. The analysis forwards a scholarly understanding of the legacy of race-conscious policies.