France is a key power - but smaller states feel left out
The meeting of European leaders in London was supposed to reinforce the impression of European unity in the American-led war against terrorism.
But it also reignited fears among the smaller EU member states that they are being given second class status in the evolution of European policy.
The President of the European Commission, Romano Prodi, said it was a "shame" that separate meetings were taking place, and other European leaders were unable to hide their irritation at being excluded.
Sunday's meeting tried to take account of some of those bruised egos.
Initial invitations were limited - again - to France and Germany.
But during the course of the weekend the guest list was expanded.
Italy, Spain and Belgium were also at the table, as well as the EU's foreign policy chief, Javier Solana.
That meant the leaders of the five countries which have offered military assistance to the US-led campaign, as well as Belgium - the current EU President - were in the same room.
British officials say that was important in upholding a "common European position".
There was still room for misunderstanding, however.
"Summits of this kind must not set a precedent for the European Union," said a Portuguese cabinet source quoted by a Portuguese news agency.
The significance of the split should not be over-exaggerated.
The smaller EU countries are always wary of being pushed around or ignored by their larger partners.
Nevertheless, the way Europe is responding to events since 11 September does illustrate again how difficult it is to produce a common foreign and security policy among the fifteen member states, in which everyone has a say every time.