In terms of wealth and population they ought to be able to match, or even supplant, the defence capability of the US. Yet in crisis after crisis all eyes turn to Washington, not only for firepower and manpower, but also for logistics and intelligence. If there is no response the handicap appears fatal; nothing much can be done. If there is a response, then with it comes the main provider's natural expectation of the political lead in defining goals and choosing a strategy.
The simple explanations for the relative weakness of the European effort point to its fragmentation and incoherence, the reluctance of many states to contribute significantly, and the need of those that do to make special provision to sustain national defence industries. A more fundamental reason, however, is that for the last half-century the Europeans have never really wanted to reduce their dependence on the Americans. At best this would be an extremely expensive undertaking, and at worst it would have dire strategic consequences.
The French said this was all wrong - that the Americans were unreliable allies exacting an excessive political price; that Europeans could look after themselves unaided. True believers in the European project at times claimed that it could never be complete until a proper defence dimension were added. Yet the mainstream view remained that all such talk was unwise. There was no evidence that France was willing to pool its sovereignty into a common European defence policy; it just wanted to get the Americans out. Yet this is precisely what most Europeans wanted to avoid. There had always been a strong lobby in the United States for cutting back on the commitment on Europe. Claims that Europeans could defend themselves unaided would provide just the excuse for the Americans to give three cheers and withdraw to safety to the other side of the Atlantic. And if the Warsaw Pact then decided to see just how strong the West Europeans were without American support, the results could be tragic.
Once there was no Warsaw Pact to worry about, the old case for an independent European defence capability was revived. Events soon refuted it again. If anything, the post-Cold-War position was worse. Questions of real military operations arose - first in the Gulf and then in the Balkans. Both turned out to be embarrassing for proponents of an independent and assertive Europe.
Britain made a decent showing in the Gulf, although what was a supreme effort was dwarfed by the size and quality of the American force assembled. Once the French had decided that they could not send conscripts, their numbers available for active service were meagre. The whole experience of Desert Storm demonstrated just how far ahead the Americans were in the infrastructure of war as well as in precision weapons. The experience eventually led to the complete reconstruction of the French armed forces - quite explicitly on British lines - and a far greater realism about what could be done without the Americans.
The impact of the Gulf War on French strategic thinking is one aspect to yesterday's summit between Prime Minister Blair and President Chirac that many commentators have missed. This has been combined with the impact of the wars over Bosnia and Kosovo on British strategic thinking.
The UN force in Bosnia from 1992 to 1995 was largely a European enterprise, and it was a nightmare, culminating in Dutch peacekeepers finding themselves in an invidious position as Srebrenica was overrun and Moslems were massacred. The UN units were too small and too weak to impose themselves on the warring parties, and were vulnerable to retaliation. The lesson drawn was that any future land operations had to be able to look after themselves, and backed by serious air power. The trouble was that the Americans, while quite willing to supply air power, were remarkably reluctant to commit ground forces. This became apparent to Tony Blair when he was arguing for Nato to take a firm line in Kosovo in the autumn of 1998. With the Americans refusing to take risks on the ground, diplomacy was undermined.
Part of the thinking behind the European initiative in London, therefore, is that there are important military options that may be lost if Europe is unable to provide the necessary forces. While it might have been unrealistic to expect the European Union to take on the combined might of the Warsaw Pact, the EU really should not be at a loss when faced with Serbia. The Franco-British proposal for a dedicated European 50,000 rapid reaction force is designed to fill the gap. The initiative is also influenced by a concern that, whether Europe likes it or not, there are formidable trends in the US encouraging an increasingly unilateralist, even isolationist stance, so Europe has to be prepared to take responsibility for its own security.
This remains a sensitive topic, as can be seen by reported American worries that the new initiative is an attempt to freeze them out. Some British Eurosceptics have warned Tony Blair against conniving in an effort to replace Nato. There are three answers to such worries.
First, the Americans themselves have long argued the need for a more credible European contribution, if they are to convince Congress that they deserve support. Second, the nature of the force planned under the new initiative is modest. It would do no more than enable Europeans to do some things the Americans might not want to do, and is certainly not the basis of a truly independent capability. Third, any operation would still be highly dependent upon the Nato command structure, and probably American logistics and intelligence. It would be hard to mount an operation against Americans' wishes.
None of this is to deny the political significance of the initiative, but it has to be understood by reference to the evolving relationship between the US and its allies, and Britain with its European partners, rather than as the latest attempt to realise the discredited dream of Nato's being replaced by the European Union.
The writer is professor of war studies at King's College, London