Focusing on the history of US anthropology between World War II and the high point of the Vietnam War protests in the late 1960s, this paper aims to historicise the assumed epistemological divide between anthropological and legal thinking. It is shown how anthropology as a discipline in the US has restructured some of its basic assumptions and changed its institutional structure in the context of legal interventions in larger struggles, specifically the court-based battles against racial segregation and the legal proceedings related to indigenous land rights before the Indian Claims Commission. Special consideration is given to an analysis of how objectivity is conceptualised in the literature on anthropological expert witnessing: from mechanical objectivity before 1970 to critical objectivity after 1970. The paper concludes with a caveat against exaggerating existing epistemological differences between anthropology and law, and suggests a more pragmatic approach to interdisciplinary communication.