Regionalism can be defined in the context of international relations as the expression of a shared identity and purpose. It is combined with the creation and implementation of institutions that manifest regional identity and shape activity within that particular region. There are a wide number of regional organisations to consider with varying levels of integration. For instance, the depth of integration within the Arab League or the Association of Southeast Asian Nations (ASEAN) is considerably weaker than the EU.

The driving forces behind regionalism can derive from economic, security and/or political grounds. The European Economic Community (EEC), the forebearer to the EU, is a clear example of economic regionalism. The creation of the European Union in 1993 was emblematic of regionalism. As a result of the Maastricht Treaty, the EU adopted three separate pillars. These pillars consisted of the European Communities, the Common Foreign and Security Policy (CFSP) and cooperation in the field of Justice and Home Affairs. This was later abandoned when the Treaty of Lisbon came into force in 2009, and the EU obtained a legal personality.

Old regionalism is rooted in the experience of interwar nationalism, and as such held a tendency towards protectionism in the economic realm. The formation of the EEC is a clear illustration of the former. Contrastingly, ‘new regionalism’ entails a more spontaneous process that emerges from within the region itself. In doing so, the process of regionalism adopts towards the dynamics of the region in question. Inevitably, some regions are more conducive towards regional integration than others. The extent to which a particular region accommodates regionalism will also differ considerably over time. For instance, the process of European integration developed from economic to political regionalism. New regionalism is a more complex process that may take place simultaneously at a variety of levels.

The result of the United Kingdom’s (UK’s) referendum on European Union (EU) membership was a major blow to the EU and will alter the future path of regionalism in Europe. There are predictions that it may well strengthen European regional integration, despite earlier concerns about disintegration, and much will depend on the relationship between Germany’s Angela Merkel and France’s Emmanuel Macron. Beyond the EU’s borders, there is also scope to consider how the UK’s exit from the EU will affect regionalism in Southeast Asia.

The prospects for political regionalism and regional governance are driven by a combination of internal and external factors. The former relates to those factors that characterise the region itself. External factors, however, relate to events that originate from outside of the region (such as the 2007–08 Global Financial Crisis). The internal forces that shape regional governance may be far greater in one area of the world than another. For instance, the devastation caused by the Second World War undoubtedly provided the impetus behind early moves towards European integration. In addition, the impact of external forces may be significantly greater in one area of the world compared to others.

In order to identify the prospects for regional governance and political regionalism, it is perhaps necessary to consider the issue on a region-by- region basis. For example In South America, regional governance has been limited by a number of familiar issues. These include the absence of economic convergence, a shift in the balance of global economic power and of course state sovereignty.

The argument that regional blocs can be utilised in order to prevent conflict is built upon the theory of neofunctionalism. According to this perspective, integration in one area inevitably creates a dynamic towards deeper integration overall. Over time, member states will make progress towards a federalist structure comparable to the United States. Neofunctionalism advocates rule by technocratic experts housed in supranational institutions.

Another important concept within neofunctionalism is that of spillover. This reflects an assumption that moves towards a more federal Europe must be achieved on a gradual basis. The creation of an ever-closer union with three discernible branches of government requires a level of legitimacy that can only be achieved on an incremental basis.

Of all the regional organisations to consider, the most significant remains that of the European Union. It has for instance provided a blueprint for other areas of regional integration (notably in Africa). The EU is also an increasingly important actor within global politics.