The purpose of this article is synthetic analysis of the theories concerning the Security and Defence Policy of the European Union. Author analyses neorealist and neofunctionalist theories and marginally takes into account theory of liberal intergovernmentalism and new institutionalism theory
  Neorealists argued that in order to understand CSDP, one should look at the changing nature of the balance of power and the way in which member states sought profits coming from the negotiation process, which took place between European Union and NATO. Liberal intergovernmetalists, including Andrew Moravcsik, assumed that CSDP is a factor created and driven by the domestic policy of member states, although both NATO and EU institutions influenced this process. Neofunctionalists’ hypothesis assumed that CSDP is a result of the spill-over effect – consequence of the economic integration. They demonstrated, through economic analysis, the impact of economic and monetary union on the process of development of the European security and defence policy. In neoinstitutionalist theory, the emergence of the CSDP is explained by highlighting the impact of international institutions in the foreign policy of the EU and NATO member states.
  Above hypotheses have the objective of finding the causes of the CSDP’s emergence, but are also an attempt to answer the question what is the CSDP. Exitisting theories do not adress the whole issue comprehensively, because they are missing implication of links between supranational, transnational and intergovernmental dimension of CSDP, indicating only the conceptualization of evolution and the role of the various bodies at different levels, particularly in the theories of neoliberalism, neoinstitutionalism and intergovernmental liberalism.