Yesterday's ceremonies to enlarge the North Atlantic Treaty Organisation from 16 to 19 member-states with the addition of Poland, the Czech Republic and Hungary are an important prologue to the alliance's 50th anniversary meeting next month in Washington. After the end of the Cold War NATO has had to invent a new mandate for itself above and beyond its original one, classically summarised as to keep the Americans in Europe, the Russians out and the Germans down.
As one commentator has put it, the Russians are now both out and down, the Germans have melded into a wider Europe that is as rich as the US itself, while Washington is keen to stay in but determined to call the shots if it bears most of the alliance's costs. NATO enlargement is regarded in the US as a triumph for President Clinton's foreign policy. He pushed it steadily against sceptics who warned it could deeply and needlessly antagonise the Russians by drawing new dividing lines in Europe precisely at a time of pressing need to heal the wounds of the Cold War.
These criticisms are no longer heard so loudly in Washington and other NATO capitals. But they are implicit in the logic of NATO enlargement beyond these three states, as nine others continue to press their case to join the alliance. Romania, Bulgaria and Slovenia are considered the most likely candidates; they would certainly be easier to accommodate than any former members of the USSR, such as Ukraine, Estonia, Latvia or Lithuania, which border directly on Russia. But it must be remembered that the enlargement demand is popular within all these states precisely because of fears for their security arising from Russian instability - despite worries about having foreign troops on their soil and the costs involved in modernising and re-equipping their armed forces when other socio-economic priorities compete.
In response to such criticisms NATO broadened its mandate to include most European states, Russia included, in the Partnership for Peace (PFP). It is proposed to deepen this structure, as a staging post towards NATO membership for some and a means of security co-operation on a broad canvass for others. The PFP still holds out the possibility of an inclusive method to deliver security, along with the Organisation for Security and Co-operation in Europe (OSCE) and a reconstituted relationship between NATO and a European Union itself enlarging to take in most of the same states in the medium term.
These changing relationships together represent a major and as yet incomplete transition beyond Cold War defence and security structures. Much will depend on precisely how NATO and the EU organise their new relationship. The initiative between Britain and France at St Malo last November is an important element in that. So is the outcome of negotiations on NATO's new strategic mandate to be agreed next month in Washington. The US would like to free up NATO to be able to operate out of its territorial area, if necessary without a United Nations mandate, a move which is resisted by France, Italy and several other European states. The developing crisis in Kosovo will be a laboratory in which many of these relationships will be developed in practice.