Protest movements are drivers of political, economic and social change. A fundamental goal of such movements is mobilisation on the basis of shared identities and common interests. This project examines whether protest - and in particular, ethnic activism - can affect the racial identities of non-protestors. I propose a new method to measure changes in racial identity using self-identified race in US social security card applications. Using a sample of individuals with Native American ancestry linked between historical censuses and social security records, I document an increase in the share identifying as ’nonwhite’ following high-profile ‘Red Power’ protests in the late 1960s. I propose to study the tangible effects of changes in racial identity on a range of short- and long-run outcomes, including the occurrence of subsequent protests, tribal enrollment, legal action against the US government, and the extent of cultural renewal later in the 20th century.