The result is that for the first time since World War II, European defence has become not just territorial defence, but also conflict prevention and crisis management within Europe, and on the EU's own frontiers. The consequence is that NATO has had to adapt to a new range of tasks, which in turn require quite different philosophies and structures from the old Article 5 certainties. That process continues today. Indeed, NATO's guarantee gave Europeans the security they needed to rebuild Europe and made it possible for the EU, in its turn, to become a producer of stability. But as with NATO, so the collapse of communism has faced the EU with the need to change.
Enlargement is one aspect of that.
But another is the need to develop the coherence and credibility of the CFSP to be able to deal effectively with political instability on the EU's borders. Until 1989, a CFSP that was limited to declarations and to economic and diplomatic sanctions was just about credible. The break up of Yugoslavia from 1990 onwards showed clearly that this was not enough. In other words, the last ten years have shown the necessity for both NATO and the EU to adapt radically to the new challenges presented by the end of communism. The crisis in Bosnia in 1992-95 before the Dayton Agreement of December 1995, showed the difficulty of crisis management without the participation of the United States.