Compare the OAU and the African Union — the doctrinal shift from non-interference to intervention.

Nature: the world's deepest integration — the supranational mark: the members' pooled sovereignty in the treaties' conferred competences; the law's direct effect and supremacy doctrine (the CJEU's construction). Development: the 1951 Coal-and-Steel Community → the 1957 Rome Communities (EEC, Euratom) → the 1992/93 Maastricht Treaty's Union (the three pillars; the EU citizenship) → the Lisbon Treaty's streamlining (the legal personality; the Charter of Fundamental Rights) → the euro, the Schengen, the single market → Brexit (the UK's 2020 exit — the first secession; the 27-state Union). Composition: the 27 members; the accession Copenhagen- criteria discipline (the Western Balkans' and the Eastern neighbourhood's queues). Institutions: the European Council (the heads of state/government — the strategic direction), the Commission (the independent initiator-and-guardian of the treaties), the Council of the EU (the ministers — the legislature's chamber with the Parliament), the European Parliament (the directly-elected chamber), the Court of Justice (CJEU) (the preliminary-ruling architecture — the integration's engine room), the ECB, the Court of Auditors. Functions: the single market (the four freedoms — goods, persons, services, capital), the customs union and the euro, the common policies (agriculture, trade — the exclusive competence; competition), the commonforeign-and-security policy's intergovernmental face, the area of freedom-security-and- justice. The EU lesson for the exam: the furthest point of the integration ladder — the states' sovereignty pooled, not dissolved.