Regional organisations are a significant feature of the contemporary international system, representing attempts by states in geographical proximity to cooperate on shared interests. These organisations vary widely in their scope, level of integration, and primary objectives. The European Union (EU) is arguably the most deeply integrated regional organisation, having evolved from a purely economic community into a powerful political and economic union with a single market, a common currency for many of its members, and supranational institutions that can create binding laws. In contrast, the Association of Southeast Asian Nations (ASEAN) operates on the principles of consensus, non-interference, and consultation, known as the ASEAN Way. While it has fostered significant economic cooperation, its political and security integration is less developed than that of the EU. The African Union (AU) has a broad mandate covering peace and security, development, and governance across the African continent, with an ambitious agenda for political and economic integration, though it faces significant challenges in implementation. The Shanghai Cooperation Organisation (SCO), which includes China and Russia, is primarily focused on regional security issues, particularly combating what it terms the three evils of terrorism, separatism, and extremism, and also serves as a platform for economic and energy cooperation.