SIX years ago, when Bertie Ahern and his delegation attended the European Council in the wake of the second Nice referendum, they were greeted with congratulatory smiles, handshakes and pats on the back.

His successor Brian Cowen can expect a much cooler reaction when he sheepishly shows up at the council on Thursday.

There are mixed views among EU watchers – varying from 'no change' to 'pariah status' – as to how badly Ireland's influence will be dented by Thursday's no vote. But at the very least the Taoiseach can expect some intense questioning as to what went wrong.

There is huge frustration across the EU that the Lisbon treaty – formed after painstaking negotiation over many years – has fallen because of the vote of one of the smallest of its 27 members. It's like a jigsaw with one tiny piece missing. Some well-placed sources in Brussels take the view that there will be an empathetic sense of 'there but for the grace of god go I' among European leaders about the position in which Cowen finds himself. Others, however, are less optimistic, believing Ireland has done serious damage to its own interests in Europe's corridors of power.

They believe other members will take a pretty jaundiced view of a country that has taken €30bn from the EU budget over the years, benefited hugely from the Common Agriculture Policy and a low corporation tax rate, turning around and deciding that, after all, they weren't that keen on the EU.

Comparisons with France, who voted against the EU constitution, are regarded as ridiculous. "We're not France," is how one observer put it. Acerbically noting the comment of one leading Tory on Friday that "we're all Irish today", they question who Ireland's allies will now be around the negotiating tables in Brussels in the coming years? A Conservative-led UK government?

There is a genuine sense of bafflement as to what happens next with the Lisbon treaty. The best-case scenario for Ireland is if another country – possibly the UK or the Czech Republic – call a halt to its ratification. That would certainly take the heat off us.

The worst-case scenario for Ireland is that not only does every other country ratify the treaty, but the country gets left behind in a two-speed EU. In theory, the instruments to do that are not there, but this is politics and anything is possible.

A second referendum for Ireland has been mooted in some quarters but politically, it is a non-runner . It's not just the margin of victory, but the wide range of reasons for the no vote. Unlike post-Nice I, there is no quick fix that would allow the issue to be put again to the Irish people.

There will be intense communications in diplomatic channels over the coming days but, until all the leaders come together next week, nobody has a clue where Lisbon goes from here.

After the tortured process to get to the point of signing off on Lisbon, there is no appetite to go back and start from scratch. But against that, there is a belief that reform is necessary and that the Nice treaty provisions do not work. So some sort of change, experts say, is inevitable.

If there is no Lisbon treaty, the old obligation under Nice to reduce the number of commissioners comes into place next year. The big worry is that a decision could be made to create senior and junior commissioners among the 27 member countries – just how a potentially friendless Ireland would fare in such a carve-up must be a concern. Other challenges lie ahead. Having used up so much of our credit voting down Lisbon, questions have to be raised as to whether, for example, we could credibly veto any world trade deal now – that would risk pariah status. The government also has to try to do a deal on carbon emissions. Pleading our case – wealthy country, high emissions – has undoubtedly got harder.

As potentially did the job of IDA Ireland. Nobody is saying multinationals will be pulling out of Ireland after the no vote. But there is little doubt that IDA Ireland's counterparts in Estonia or Latvia will be privately delighted at the development. In the competitive business of attracting foreign investment, the smallest things make a huge difference.