The European Union’s institutions are;
• the European Parliament,
• the European Council,
• the Council,
• the European Commission (hereinafter to as ‘the Commission’),
• theCJEU of the EU,
• the European Central Bank,
• the Court of Auditors.

One of the leading scholars on the European integration, Ernst B. Haas defined integration as a process “whereby political actors in several, distinct national settings are persuaded to shift their loyalties, expectations and political activities toward a new centre”. The end result of a process of political integration is a “new political community, superimposed over the pre-existing ones”. Political integration is usually identified with the emergence of a political community based on trust, loyalty and shared values. On the basis of Haas’ definition, it is both useful and necessary to differentiate between the sub-dimensions of political integration below:

• Policy integration
• Institutional integration
• Civilizing/security dimension
• Attitudinal dimension

Attitudinal integration is concerned with the sources of support or opposition to regional integration among the public at large and among the political and economic elites. Attitudes affect the development of policy and institutional integration. For instance, European public support for a more effective, credible and coherent EU foreign policy as well as external demands and expectations are one of the key factors shaping the actorness of the Union. It is also important to recognize the transformative nature of the European integration: transformation of the nation-state by the EU and transformation of the EU by the member states and the contradictory and differential impact of globalization on the EU.

The European Council has emerged over the last four decades as the most powerful among/in the traditional Community institutions. It exercised several functions without any legal treaty basis for them, ranging from providing strategic guidelines, decisionmaking capacity in economic governance, foreign and security policy and amending the treaties. The Lisbon Treaty has put an end to the paradoxical status of the European Council by identifying it as one of the seven EU institutions.

Constitutionalization is the formalization of the rules of the game, which in an EU context, might involve a process whereby the treaties become over time.

In the transactionalist model, integration has two key dimensions. The first is a process of social integration, leading to the formation of pluralistic security communities. The formation of security communities relies on the notion that international transactions—communication, migration, mutual services, military collaboration and so forth trigger the process of social-psychological learning which in turn produce common identities and trust among social actors. The second dimension is the process of political integration. Once pluralistic community formation has taken place, political elites may opt to build common supranational institutions, thereby producing ‘amalgamated’ security communities (essentially federal unions).

The post-Maastricht phase of European integration has become associated with the new research agenda of post-functionalism. This theory postulates that functional pressures no longer continue to play a major role in the European integration. Instead, integration has become vulnerable to changes and developments in domestic political contexts and notably to greater political and cultural (identity-based) political party and public contestation around the issues of the European integration.

Optimum currency area is a currency area in which costs and benefits of sharing a single currency is balanced.

For Nicole Scicluna, the demise of the Constitutional Treaty as a result of the French and Dutch “no” votes demonstrate an unsuccessful attempt at “democratization via politicization”. The Constitutional Treaty was drafted with the interrelated aims of filling the symbolic gaps of Europe, facilitating the growth of European demos, and bringing the Union closer to citizens. Its defeat in 2005 triggered a process of de-constitutionalization that culminated in the Lisbon Treaty of December 2009.

Therefore, the type of state structure of a Member State, for instance whether it is a republic or a monarchy, the governmental system of a Member State, for instance whether it is a parliamentary, presidential or a semi-presidential system, whether it is a federation or a unitary state as such are determined by those Member States themselves. The EU does not have the power to regulate those issues; in fact it has to respect the constitutional structures of its Member States. However, the Member States, despite being free to design their own state structure, should respect and embrace the fundamental values of the Union which are enshrined in Article 2 of the TEU. Consequently, whatever state structure is adopted by a Member State, this structure should demonstrate the basic requirements of democracy, respect for human rights and rule of law, amongst others.

The European Council consists of the Heads State or Government of the Member States, with its President and the President of the . Since it is the institution comprising
the highest political representatives of the Member , those heads of state represent their own ’ national interests.

Post-Maastricht European integration which is mostly regarded as the new intergovernmentalism is a contentious issue.

Early integration theories such as federalism, functionalism, and transactionalism took an account of
the origin and nature of integration, the contemporary integration theories such as neofunctionalism, intergovernmentalism, and liberal intergovernmentalism have sought to analyze how and why the EU emerged and how it works on a daily basis.