Most historiographical currents examining the history of human rights postulate a clear break between the collective rights tradition of interwar minority protection and the ensuing age of individual human rights. Two observations, however, suggest a more nuanced account of the transition from the League of Nations’ to the United Nations’ rights systems. First, the minority treaties were a hybrid system containing a mix of individual and collective rights provisions that enabled interwar rights advocates to use them as a model for the adoption of human rights instruments. Second, at the end of WWII, several delegations at the UN strongly defended the inclusion of elements of interwar minority protection within the Genocide Convention (GC) and the Universal Declaration of Human Rights (UDHR). Although these efforts were unsuccessful, they show that there was no consensus in favour of an exclusively individualist conception of human rights. More importantly, opposition to the inclusion of minority protection clauses came from Western diplomats who defended their governments’ prerogative to promote the assimilation of the people inhabiting their territory into the majority culture of the state. Therefore, what prevailed during the drafting process of the GC and the UDHR was an assimilationist interpretation of human rights; one that in a context of national heterogeneity promised to favour the rights of some groups (national majorities) over those of others (national minorities).