This study aims to set out out and understand the very contrasting political responses two western liberal democracies - France and Britain - have developed to deal with the political, social and moral dilemmas posed by the integration of distinct ethnic and racial groups. It goes about this task by focussing on the central policy debates taking place in the two countries during the 1980s and 1990s over dilemmas raised by the integration of such problematic groups, particularly those of Islamic origin. It explores how the language and terms of political debate in each country have centred around particular concepts and theories put forward to justify policies towards these issues. It is thus a work of normative political analysis, addressed to arguments it reads as definitive of each national case. It draws upon the work of influential intellectuals and academics, high level official political discussion and formulations, legal jurisprudence, and the reflection of these arguments in public discourse. Understanding the debates and the normative arguments and theories they embody, will thus focus on setting out the kind of issues around which arguments turn. In the two countries, very different conceptualisations of key ideas such as ‘citizenship’, ‘pluralism’, ‘equality’, ‘liberty’, ‘autonomy’, ‘public order’ and ‘tolerance’ are at the centre of the debate, together with very distinct umbrella frameworks of ‘intégration’ or ‘multiculturalism' and ‘race relations’. In both cases, the policy frameworks during the 1980s have converged on an official public political theory - a ‘public philosophy’ - of how social integration under conditions of value pluralism can best be achieved and rendered compatible with more traditional ideas about their respective national traditions and political practices. The thesis is broadly divided into two parts. The first part sets out a theory of public policies as normative and explanatory theories, which suggests how a dominant theoretical model (a set of ideas shared across party lines) can provide the focus for a consensus on policy towards the integration of ethnic minorities. This is an area of policy characterised both by the paradoxical dilemmas it sets for the conventional principles of western liberalism, and the controversy and under-determination of scientific knowledge about race, culture and ethnicity and the securing of social order in pluralist societies. I go on to read the dominant policy frameworks found in France and Britain, showing how they emerged in recent years, and analysing the normative and explanatory ideas and assumptions they use to found their approach to the question. In the second part, I develop a theory of the ‘path dependency’ of these models, which helps both explain the direction and development of national policies in recent years, and how over time the institutional frame has constrained and delimited their rational adaptation to new circumstances. 1 thus go on to read the dilemmas that have characterised the politics of France and Britain towards ethnic minorities during the 1980s - spectacular events such as l'affaire du foulard and the Rushdie affair, and heated controversy about the reform of nationality and immigration laws - as ‘institutional pathologies’, blocking in particular the convergence and coordination of policy making at a European international level. The thesis aims to offer findings and theoretical reflection of interest to the disciplines of applied political philosophy and comparative policy studies, as well as the sociology of race and ethnicity.