WHATEVER happens in the coming days and weeks – and nobody, even in Fianna Fáil, has much of a clue as to how this story is going to develop – there is no shaking the feeling that something changed irrevocably after Brian Cowen's disastrous Morning Ireland interview last Tuesday.

It may not be the end of his tenure in the office of the taoiseach, but surely it is the beginning of the end.

Whether that is fair or not is beside the point. Perception (sadly) is everything in modern politics and even the Taoiseach's most ardent admirers in government circles (and they are a shrinking number) accept that it will be difficult, and perhaps impossible, for him to recover from the perception that he unwittingly created last week.

The image of him singing songs and doing impressions in the Ardilaun hotel bar into the early hours and then stumbling his way through an interview with Cathal Mac Coille a few hours later will take some shifting from the public consciousness, as will Simon Coveney's tweet that the Taoiseach sounded half way between drunk and hungover.

It doesn't matter that even his critics in the parliamentary party swear Cowen wasn't the worse for wear the previous night. The damage has been done. In politics, that most unforgiving of professions, once you are explaining you are losing.

Peter Brooke found that out nearly 20 years ago when he got in front of a microphone on the Late Late Show to sing 'Oh my Darling Clementine' just hours after eight workers had been killed by an IRA bomb. Like Cowen on Tuesday morning, the then northern secretary didn't do anything wrong. He hadn't even wanted to perform but was coaxed into doing so, probably finally relenting out of sheer politeness. But within a few weeks he was gone from the British cabinet. Instead of being remembered for his historic statement about Britain's lack of "selfish, strategic or economic interest" in the North, Brooke will forever be identified with his unfortunate decision to sing on the Late Late.

But whereas Brooke's gaffe came out of nowhere, the same cannot be said of Brian Cowen. Nobody doubts the respect Cowen has for the position he occupies but it is known that friends have been urging him to address his lifestyle for some time. Even if the interview with Morning Ireland had gone well, questions have to be asked about his judgement in being in the bar at such a late hour, doing comedy routines before a room full of journalists.

In an ideal world, the taoiseach of the country would be able to let his hair down and get away from the obvious pressures of the job. But we don't live in an ideal world. A politician as savvy as Cowen should know that. It reflects well on his humility and integrity that he is determined not to be changed by the office of the taoiseach and to be the same man he always was. But it is also hopelessly naive. He cannot be the same man he was. Could anyone imagine Barack Obama or Tony Blair or David Cameron leaving themselves so exposed?

But then all those politicians understand what is required of a modern leader. Cowen has always despised the politics of spin, believing a leader should be judged by what he does and not what he says. Clearly uncomfortable in the spotlight, he refuses to play the media game and, unlike his predecessor Bertie Ahern, is unable to mask his frustration at the media's shortcomings.

After the Ahern years of leadership by focus group, there is something admirable about this approach. But it doesn't work in the modern era, an era in which meaningless soundbites like "Yes we can" and ridiculous autobiography titles such as The Audacity of Hope are de rigueur.

Cowen may indeed, as his supporters claim, be a "classic example of substance over style" but unfortunately style trumps substance every time.

Cowen's future hangs in the balance this weekend, although no imminent challenge looks likely. That much is clear although not much else is. Talk to 20 Fianna Fáil TDs in recent days and you will get 20 different assessments of what is going to happen. They do however agree on certain things:

* Cowen is badly damaged – some say irrevocably – by last week's events.

* There is a growing number of TDs in the party – up to 30 and some say over 30 – who want him gone.

* If a senior cabinet figure comes out against Cowen, he is in serious trouble and probably finished.

* Phone calls are being made by backbenchers to senior ministers disgusted at what happened in the Ardilaun and urging them to act.

* If Brian Lenihan had not had his health problems, he would become leader and possibly would have done so before now. While the leadership is not currently an option for the finance minister, he is the "kingmaker" and whoever he supports will be the leader.

* Unless a senior figure comes out, no motion of confidence will be put to the Fianna Fáil parliamentary party.

* Cowen's strongest card now is the fear that another change of leadership would precipitate a general election.

Micheál Martin, who is seen as close to arts minister Mary Hanafin, is most likely to present a challenge to Cowen, although some in the party believe his "lessons to be learned" assessment had more to do with securing his own seat in Cork South-Central, where private polls have shown him at risk, than with a bid for the leadership.

Several TDs told the Sunday Tribune this weekend that calls were being made on Martin's behalf to test the waters, but it is far from certain that Martin authorised such contacts.

"Micheál is a long way from putting his head above the parapet," was the assessment of one very experienced Fianna Fáil deputy.

Views are sharply divided on whether Cowen can survive but there is a growing view at all levels of the party that he cannot lead Fianna Fáil into the next election.

"His goose is cooked. He's badly damaged. It could happen as early as next week," one government TD said. "He's holed below the water line and he's in choppy seas. It's just a question of when he sinks," was the verdict of another Fianna Fáil source, while one highly influential backbencher said there had been "a shift from people who've supported him in the past".

But other deputies insist there will be no challenge to the Taoiseach. Donegal North-East TD Niall Blaney expressed his "full confidence" in Cowen, saying he had taken the country through "an unprecedented period" that "I don't believe any other leader would have led us through".

But such bullish support for the Taoiseach is a rarity and most of those arguing Cowen will survive do so for entirely practical reasons. They say no minister will come out against him and that there is a fear of bringing about a general election.

"There is no other option. People are scared of losing their seats. Many of the younger ones have no jobs to go back to, no pensions. The Dáil would not wear a second change of leader without an election. Brian Lenihan is probably the only one who could do it and get away with [because of his popularity with the public]," one Cowen-supporting TD said.

Another TD, asked if he wanted Brian Cowen to stay on as leader, replied: "I do, because his removal will cause an election." Another answered the same question with, "Yes, because it's too late to change" – hardly ringing endorsements.

"The biggest thing he has going for him is that his exit would necessitate a general election. That's the only hand he has left. In terms of credibility and standing, he's finished. My best guess is that nothing will happen [in the short term] but he won't lead us into the next general election," said one influential deputy.

The claim that a change of leadership would precipitate a general election is disputed by some deputies. They say an election is probably inevitable next year anyway and that a new taoiseach could buy time until then by stating that first he or she had to introduce a budget and bring finality to Anglo Irish Bank.

However, other TDs fear that not only would this not wash with the public but that the Greens might see it as an ideal opportunity to leave the government by insisting that the new leader has to seek a mandate from the people before becoming taoiseach.

Where all these conflicting views will lead to is anybody's guess. Some deputies predict that the next opinion poll will decide a lot.

"It's so uncertain at the moment. There's an element of 'wait and see'. Nobody wants to be seen as the first mover," said one TD.

And, of course, if nobody moves then Cowen will remain in situ, albeit badly wounded. If the budget goes through, Anglo is parked and Cowen succeeds in raising his game and looking the part, it is still possible he will lead Fianna Fáil into the next election. But with three by-elections to come, it is surely unlikely.

Numerous colleagues spoke privately last week about how, considering his decency, honesty and integrity, it would be "tragic" if the events in Galway came to define Cowen's tenure as taoiseach. But political outcomes are seldom fair.

Just ask Peter Brooke.