This thesis investigates federalism and civil conflict. Past work linking federalism and civil conflict has investigated the factors that pacify or aggravate conflict, but most such studies have examined the effect of decentralization on conflict onset, as opposed to the form federalism takes (such as congruent vs incongruent forms, for example). I collect data on civil conflict, the institutional characteristics of federalist states and fiscal decentralization. My theoretical expectations are that federations who treat federal subjects differently than others, most commonly in an ethnically based manner, are likely to experience greater levels of conflict incidence and more severe conflict. I find support for these expectations, suggesting more ethnically based federations are a detriment to peace preservation. I close with case studies that outline three different paths federations have taken with regards to their federal subunits.

Asymmetry and executive federalism are two unique features that dominate the Canadian political landscape. As a result, federal and provincial governments are in direct negotiations over many current public policy issues, immigration policy notwithstanding. In order to understand the current immigration debate and to evaluate the benefits of greater provincial involvement, it is first necessary to comprehend what motivates provinces to be active in immigration policy-making. Ontario presents an interesting example of a province that used to be quite content with leaving the federal government dominant in the immigration arena but that has recently changed its attitude completely: Ontario is now much more assertive in presenting its demands. Through a comprehensive literature review and a series of interviews of key immigration policy figures, this study analyzes the main motives of Ontario with respect to immigration policy. It finds that they were primarily of economic, demographic, and political nature and that they were mainly connected to the relative decline of Ontario's position within Canada.

La différenciation entre les États membres de l’Union européenne s’est progressivement transformée en un leitmotiv du débat sur l’avenir de l’intégration. Ce débat a resurgi avec l’activation de la clause du retrait par le Royaume-Uni, qui pose dans un cadre renouvelé la question de la compatibilité du processus de création d’une « union sans cesse plus étroite » avec la possibilité pour les États membres d’emprunter différentes voies d’intégration. L’objectif de la présente étude est d’apporter un éclairage sur cette question, en se focalisant sur l’amplification des manifestations de la différenciation en droit positif. La première partie de l’étude vise à cerner la tension entre l’uniformité du statut d’État membre de l’Union et la participation asymétrique des États aux actions engagées pour la réalisation des objectifs assignés à l’Union. La différenciation s’avère ainsi un facteur de relativisation de l’homogénéité du statut d’État membre, sans néanmoins mettre en cause son unicité en tant que catégorie juridique. La seconde partie s’intéresse aux effets de la différenciation sur la structure de l’Union. La prise en compte de la différence d’implication des États n’est pas sans incidence sur le système institutionnel et juridique de l’Union, sans que cela traduise un désordre affectant l’intégrité de l’Union. Il devient alors évident que, dans la creatio continua que constitue la construction européenne, la différenciation pose une question de degré, plutôt que de principe. / Differentiation between the Member States of the European Union has gradually turned into a leitmotif of the debate regarding the future of the European integration. This debate re-emerged in the context of the activation of the withdrawal clause by the United Kingdom, by raising once more the question of the compatibility of the "ever closer union" concept with the possibility for the Member States to follow different paths of integration. The aim of this study is to clarify this question by focusing on the amplification of the various forms of differentiation in positive law. The first part of the study aims to identify the contrast between the uniformity of the EU membership and the asymmetrical participation of the Member States in actions undertaken to achieve the objectives assigned to the Union. Differentiation proves thus to be a relativizing factor of the homogeneity of the Member State's status, without, however, questioning its uniqueness as a legal category. The second part of the study focuses on the effects of differentiation on the structure of the Union. The different extent of participation of each Member State in EU policies has an impact on the Union's institutional and legal framework, even though this impact does not create a disorder affecting the integrity of the Union as such. It is thus apparent that within the creatio continua of the European construction, differentiation poses more a question of degree rather than principle.