The key hypothesis of the MIGJUST research project (which is funded by European Research Council grant ERC-AdG-2023- 101141743) is that there is a fundamental conflict in human rights case law on migration between the human rights approach, adopted by the Inter-American Court and Commission of Human Rights and the African Court and Commission of Human and Peoples’ Rights, and on the other hand the sovereignty approach of the European Court of Human Rights. The difference is also at work in the case law of the UN human rights bodies. The two approaches are reflected in, and are in turn reinforced by, political theory on migration justice. In academic studies, the conflict has not been noted because the case law of the European Court of Human Rights is considered to constitute the most developed version in international human rights law. The conflict between the two approaches is problematic because it goes against the international character of international law and hinders international cooperation. MIGJUST will address this problem by (a) analysing the under-studied case law of the Inter-American, African and UN human rights bodies; (b) carrying out a comparative analysis of the European, Inter-American, African and UN case law in the field of migration; (c) relating the varying positions to political theory on migration justice; and (d) developing methodologies to resolve the doctrinal conflict.