Functionalism is a theory of international relations that arose during the interwar period principally from the strong concern about the obsolescence of the state as a form of social organization.
[1] Its roots can be traced back to the liberal and idealist traditions that started with Immanuel Kant and goes as far as Woodrow Wilson's "Fourteen Points" speech.
The functionalist approach excludes and refutes the idea of state power and political influence (realist approach) in interpreting the cause for such proliferation of international organizations during the interwar period (which was characterized by nation state conflict) and the subsequent years.
The benefits rendered by the functional agencies would attract the loyalty of the populations and stimulate their participation and expand the area of integration.
Neofunctionalism is simultaneously a theory and a strategy of regional integration, building on the work of David Mitrany.
Political spillover is the creation of supranational governance models, as far-reaching as the European Union, or as voluntary as the United Nations.
The activities of functional international organizations involve taking actions on practical and technical problems rather than those of military and political nature.
They are also non-controversial politically and involve a common interest to solve international problems that could best be tackled in a transnational manner.
[11] As a result, the idea of decentralization prevails to the present day except in cases of special cooperative relationships between Economic and Social Council and some functional organizations.