As Ireland prepares to assume the chair of the UN Security Council, the Taoiseach has very significantly qualified Irish support for any US response to the murderous attacks on New York and Washington.
Mr Ahern yesterday echoed the views of his EU colleagues that while they wish to tell the US that they stand with them against terrorism, that support is not unconditional. For Ireland, the point is a particularly delicate one to make, and it is highly significant that the Taoiseach made it.
The State's "special relationship" with the US - fed by centuries of emigration and recent massive US investment - means the Government is loath to sound equivocal about support for the US in its time of crisis.
Yet other political pressures resulted in the Taoiseach yesterday stopping short of unconditional support for Washington as it considers how to react. Mr Ahern echoed the view of Mr Tony Blair and other EU leaders that while they must show the utmost solidarity, there is no "blank cheque".
He said the matter was for the international community, and not just the US. And he specifically questioned the wisdom of an attack on Afghanistan - currently seen as the most obvious military response.
Asked on RT╔ radio if the Government's offer of support for the US was unconditional, Mr Ahern said: "No, I think that's the point." The US response had to be kept within UN rules, he said.
It was most important in the days ahead, said the Taoiseach, that it is kept as an "international issue" and not just an American one. Afghanistan, he noted, was a poor country.
"It is an easy thing to bomb territories where people are in famine, but that will not do much to crush international terrorism." People would be happier, he said, if Osama bin Laden's training camps were the places which were hit.
Giving the most obvious lesson learned from Ireland's decades of experience, he remarked: "We have realised in this country that trying to beat terrorism is not that simple an issue."
The Taoiseach's clear reservation of the Government's position is an important statement of independence from the US as the Government prepares to take its turn in the Security Council chair on October 1st.
By then the global response to the attacks on the US may well have begun, and to be under constant review.
There is speculation in Dublin that given the magnitude of the task, the Minister for Foreign Affairs, Mr Cowen, may spend a considerable amount of time at UN headquarters in New York during the month-long chairmanship.
For as Ireland seeks consensus on the Security Council, it will have its own diplomatic position being pulled severely in different directions.
Firstly, we will try to act in concert with our EU partners when possible, and the EU has always laid more emphasis on diplomatic engagement with some Arab states seen by the US as enemies. Secondly, Ireland will want to minimise any damage to its particularly good relations - and important business links - with many Arab states.
And thirdly, there is the question of military neutrality. The EU's diplomatic immediate response involved a concerted attempt to ensure the US did not retreat into isolationism but sought their agreement for any response. European leaders, including the Taoiseach and Tβnaiste, described the attacks as an assault on democracy and therefore on states throughout the world, not just on the US.
The implication was that the response must come from the global community acting in concert, not the US alone.
There is relief in Europe that the US has not launched an immediate and fierce military strike against some hastily chosen target. The US administration has made clear that it wishes to build a global coalition behind a response.
Ireland rushed to show unambiguous solidarity with the US through Friday's unprecedented public holiday, a move that was noted in US media and resulted in a weekend CNN interview with the Taoiseach.
However, the desire to seem as pro-American as possible will come under strain when military strikes are under consideration.
Should the US and EU member-states agree on military action, as one of the few non-members of NATO in that Western coalition, we will not be able to rally quite so easily behind any bombing raids and other attacks.
The need to be seen to adhere to traditional military neutrality - as well as the limited capacity of the Defence Forces - rules out actual participation in any military response. The Taoiseach made this clear in his CNN interview on Saturday evening.
However, the pro-neutrality lobby will demand that Ireland also refuse permission to military aircraft seeking to overfly Ireland, or even refuel on Irish soil, if an aggressive military strike is planned.
While the prospect of NATO powers seeking to overfly Ireland on the way to some as yet unidentified target in the Arab world is uncertain, the notion of having to suggest to the Bush Administration that they take an alternative route would make many Irish diplomats shudder.
If military action has a UN mandate, this problem is unlikely to arise, as it can be portrayed as a global act of self-defence, not simply a US strike against an enemy.
Ireland's strategy will therefore be to seek a response with the maximum international legitimacy, and therefore one it is comfortable in supporting.