This chapter would focus ort European security policy to question which institution, the European Union (EU) or North Atlantic Treaty Organisation (NATO), can provide the best security environment for Europe. This is because the EU has limited border controls opened; no external military threat on its common borders and has embraced a singularity in security of states and individuals. Such singularity would be hard to achieve in a single institution disjointed from the economic and social base of trans-national communities with multiple identities which is a problem that NATO faces in operational duties nor by alienating a superpower by excluding its membership which any proposed European military union would have to come to terms with. It would, however, also be foolhardy to have duplication of effort with divided limited resources in two separate institutions. The question that this chapter poses is thus a prime focus for debate in the member states of both NATO and the EU, in seeking enlargement in 2002.