European integration has in general proceeded by virtue of 'constructive ambiguity', a combination of open-ended commitments and ambivalent formulations. The current enlargement, which concluded in April and May 2004 with the near-simultaneous entry into NATO and the EU of a group of Central European countries, was quite typical. From now on, however, addressing the issue of the foreseeable borders of the enlarged Union (and NATO too, for that matter) is crucial for shaping a credible, coherent and effective menu for action not only in and around Europe itself, but also - hopefully - in the wider world. The central European newcomers can play a crucial role in this process, especially if they actively contribute to formulating policies that may be broadly acceptable to all EU members.