One of the most startling signs of the momentous changes in the Union is the flow of uniformed military who now stream in and out of the EU Council building every day.
The EU, like it or not, is now a military power, with the limits to its role set out in the Amsterdam Treaty: peacekeeping, humanitarian tasks, crisis management, and the more controversial "peace-enforcing" where there is no peace to keep.
But at the Helsinki Council in December 1999 the heads of government pitched their ambition high - the ability by 2003 to deploy a 50,000- to 60,000-strong rapid reaction force at 60 days' notice, and sustain it for a year. And they have also committed themselves to creating a substantial international civil crisis management capacity involving police and expert personnel. Such a deployment will require rotation, and so the commitment is effectively to have at least 150,000 troops capable of working together under a common command, with all the specialist units that entails.
In Ireland's case, if we are to sustain the current deployment of 9 to 10 per cent of our military abroad as a commitment to this force, as much as a fifth of the Defence Forces will have to be trained and equipped for such duty.
Scenario analysis is under way to establish the requirements of such a force, and in November the EU will have a capabilities conference to spell out how much each state is willing to commit to the headline goal. The great unasked question - how much will all this cost? - is then likely to arise.
Within the Union's Council of Ministers, new military and diplomatic staff have been recruited for the committees that will service the new ambassadorial-level Interim Political and Security Committee (COPSI).
Key questions about the relationship to the North Atlantic Treaty Organisation (whose assets the Union will have to borrow) remain to be answered. The French prefer arms-length dialogue, while others insist on the direct participation of Nato experts in the EU planning process. Non-EU European NATO countries such as Turkey and Norway are also insisting on full involvement.
While developing the ability to project the Union on the world stage as a military power, the Union is also engaged in a radical reform of its cumbersome external aid procedures and priorities. An attempt is being made to co-ordinate the use of diplomatic resources of the member-states at the service of the Union as a whole.