The United Kingdom and France are frequently invoked as the antipodes of migrant integration policies. The author concludes that while the alleged polarity is not perfect, neither is it grossly inaccurate. He explores the sources of differences in political discourse and official practice. One is the respective processes of decolonization, very gory in the French case. Another is the respective sources of the state’s legitimacy and the absence in the British case of repeated ruptures in the political order over the past two centuries. In the United Kingdom, the threat of Muslim political domination much less replacement of the white Christian-background population is not a salient theme in fiction or intellectual discourse. One demographic difference is the large number of Hindus, Eastern Europeans, Portuguese, and Afro-Caribbeans in the British ethnic mix. At an early point in post–World War II migration, political leaders declared mutually respectful multiculturalism a paradigm for relations among citizens. Though criticized by the prime minister in 2011, its defenders, like Lord Bhikhu Parekh, are prestigious in British life. Terrorist incidents have undermined the multicultural paradigm and have led to a comprehensive effort to identify youth susceptible to recruitment by either radical Islamists or the extreme right.