Racial categorizations have been used since antiquity as grounds for assigning and takingaway citizenship. This history includes cycles of racialization and deracialization. Theproto-racialization of citizenship in Athens was followed by a more open Roman model.The racialization of religious bigotry did not become formalized until the creation of anti-Jewish and anti-Moorish policies in sixteenth century Iberia. Examining the historicalrecord across diverse contexts suggests that jus sanguinis is not inherently racist. Whilein an abstract sense, jus soli might sustain a civic vision of nationality, in practice, theexamples of Western Hemisphere states, particularly the United States, shows that jussoli is fully compatible with racialized citizenship. The construction of nation-states fromempires is consonant with the racialization of policies while the consolidation of thenation-state system created barriers to racialization. Since the mid-twentieth century,citizenship has entered a deracializing phase, even as political entrepreneursaggressively test the strength of anti-racist institutions.

Pre-arrival integration tests used by European countries suggestdiscriminatory measures subtly persist in immigration laws. Thispaper draws on a comparison across the Americas and Europe toidentify and explain historical continuities and discontinuities in‘assimilability’ admissions requirements. We attribute legal shifts atthe turn of the twenty-first century to the institutionaliseddelegitimisation of biological racism and the rise of permanentsettlement immigration to Europe. Efforts to reduce Muslimimmigration largely motivate contemporary European policies, butthese policies test putative individual capacity to integrate ratherthan inferring it from a racial group categorisation, as didhistorical precedents in the Americas.