As thousands of EU officials stood silently at noon in Brussels yesterday, the display of solidarity was unequivocal. For three minutes, the everyday rivalry between Europe and the United States was swept away in an expression of deeply felt grief.
This week's attacks in New York and Washington provoked an unusually unified response from Europe's capitals, as they lined up one-by-one to offer support in a time of crisis.
But as the world united in mourning yesterday, differences began to emerge among European states over the role they should play in President Bush's "war against terrorism".
When NATO's 19 member-states met in Brussels on Wednesday, they agreed for the first time in the alliance's history to invoke its collective security clause, known as Article 5.
Declaring that the attack on the United States represented an attack on them all, they promised to support and help Washington if the attacks came from outside the country.
Unlike a similar clause in the treaty that established the Western European Union (WEU), NATO's Article 5 does not oblige member-states to go to war if one of their number is attacked. Each member-state is simply required to take "such action as it deems necessary" to support the ally that has been attacked.
Norway's Foreign Minister, Mr Thorbjoern Jagland, declared bluntly as he left the meeting that his country was not at war with anyone.
The following morning, Germany's Defence Minister, Mr Rudolf Scharping, played down the significance of the resolution.
"We are not on the verge of war. We face the question, what is an appropriate answer - not in the sense of revenge or retaliation but in terms of the dimensions of international terror, to be able to combat and break its brutality and its effectiveness in the long term," he said.
German officials stressed that the resolution did not change the fact that parliamentary approval is needed for most decisions to send German soldiers on missions abroad. With an election due next year, Chancellor Gerhard Schr÷der will be reluctant to provoke a split over the issue within his centre-left coalition.
The Prime Minister of France, Mr Lionel Jospin, stressed that any response must be reasonable.
"We must vigorously condemn and combat terrorism. But we must not allow ourselves to be led into considerations of a conflict between the Western world and the Islamic world, where we have many friends and partners," Mr Jospin said.
Despite its historical uniqueness, this week's NATO resolution is more significant politically than in military terms. It represents a commitment to share responsibility for any action the US takes in response to the attacks. Even if few of Washington's NATO partners agree to take part in a military operation, the resolution will ensure any criticism of US plans will be muted.
In military terms, the US is unlikely to need much help from its allies and may prefer to form a smaller coalition with key partners.
Military experts suggest British and French light forces could be useful in limited attacks in Afghanistan. But what Washington needs most from its European partners is political support for whatever action it chooses to take.
Perhaps more significant that this week's NATO resolution was a joint declaration by the alliance and Russia, condemning the attacks in the US and promising to co-operate in combating terrorism.
Russia wants to join the West in fighting terrorism and would welcome a strike against Osama bin Laden and the Taliban in Afghanistan, both of whom Russia believes to be helping Chechen rebels. Russia could offer invaluable help to the US in an assault against Afghanistan.
For many EU officials, the murderous attacks in New York and Washington have underscored the need for the United States to resume its role as a peacebroker, particularly in the Middle East.
Mr Joschka Fischer, has been in intense telephone contact this week with his Israeli counterpart, Mr Shimon Peres and the Palestinian leader, Mr Yasser Arafat.
Anxious about the consequences of an ill-considered revenge attack in response to this week's outrage, Germany's Foreign Minister, Mr Fischer believes what the world needs now is patient, thoughtful diplomacy.
"Politics must not go away and it will not go away," he said.