As they made their way out to Montrose, all six had reasons for optimism about the week ahead. For Bertie Ahern, the prospect of becoming the first Taoiseach since de Valera to win three successive elections, while under threat, was still very much alive; Enda Kenny and Pat Rabbite, meanwhile, had reason to believe they were on the verge of achieving the impossible and securing enough new seats to form a government. It looked like Trevor Sargent would be there with them, leading the Greens into government after a quarter-century of being on the fringes. Gerry Adams had already seen his party in government in the North and Sinn Fein looked well-placed to hold the balance of power in the new Dail. Michael McDowell must have known some seat losses were inevitable but, with four or five TDs, he still had the chance to emulate his predecessors Des O'Malley and Mary Harney and lead his party into government.

Obviously, all six couldn't succeed.

Every election throws up casualties among party leaders. But few people would have taken a bet on none of them being around by the next general election . . . yet, just 12 weeks on, that must be considered a distinct possibility.

Already, two of the six have fallen on their swords. McDowell had a disastrous election, losing his own seat and presiding over meltdown for his party. He exited politics even before all the votes were counted.

Sargent did what nobody expected him to do and fulfilled his promise of not leading the party into coalition with Fianna Fail. It was a typically honourable gesture by Sargent, although the more politically pragmatic might question why he gave that commitment in the first place.

So then there were four. But it is far from guaranteed they will still be around as party leaders by the next election.

Ahern has already signalled he will not be. The Taoiseach says he will go at 60 but given that that won't be until September 2011 . . . by which time the next election could well be over . . . he is much more likely to step down some point after the local and Euro elections in 2009. Given his difficulties with the Mahon tribunal, the possibility of him going earlier than that cannot be entirely ruled out.

Adams' position as president of Sinn Fein is impregnable. However, he will be 60 next year and, after well over 30 highly stressful years as a central figure in the North, it would be understandable if he were keen to make way for a younger man or woman. More pertinently, it is difficult to see the merits of Sinn Fein contesting another general election in the south with a Northern leader.

For years, Adams' popularity rating in the south has been second only to Bertie Ahern's. But Adams was far from an asset for Sinn Fein during the election . . . particularly in the leaders' debate when he appeared to have little feel for politics and the main issues south of the border.

No party analyses its victories and, more importantly, its defeats more closely than Sinn Fein. While the party strongly emphasises its 32-county presence, senior party figures will know that politics in the south is very different to the North.

And it would be a surprise if they were not, at least, looking at the idea of having a joint Northern and southern leadership to avoid a repeat of last May's problems.

Like Sinn Fein, Labour had a very disappointing general election and there must be question marks about whether or not Rabbitte will still be leader by the end of 2008. The rumblings of discontent in the party are unmistakable. Labour's problems go a lot deeper than the leadership.

Rabbitte is right . . . Labour has a brand problem. The party's values may be very dear to the faithful but they are clearly not striking a chord with voters in the new Ireland. The failure of Dominic Hannigan, Labour's bright hope for a seat in the commuter belt constituency of Meath East, is surely irrefutable evidence of that.

Changing the leader will not alter that fact. However, with an ageing parliamentary party deeply frustrated at the prospect of yet another five years in opposition, Rabbitte may not be given a second chance.

In contrast to Labour, Fine Gael had a very good election, winning 51 seats and coming pretty close to pulling off a sensational comeback after the debacle of 2002 to achieve power. That performance means Kenny, assuming at 56 he wants to stay on for another four to five years, is untouchable for now. However, Kenny will know John Bruton won 54 seats in 1997 and three-and-a-half years later he was ousted. Nobody can take away from Kenny what he has achieved since becoming leader in 2002 . . . resuscitating a dying party . . . but the question still lingers as to whether he can become Taoiseach, particularly after the way Ahern clearly got the better of him in the crucial leaders' debate.

Kenny is safe until the 2009 local and Euro elections but, with Fianna Fail unlikely to fare as badly as they did in 2004, it is by no means inconceivable that he will come under pressure after that.

There are precedents for general elections being contested with all the main parties having new leaders . . . in the elections of 1961 and 1981, Fianna Fail, Fine Gael and Labour all had different leaders from four years earlier. But the possibility of it happening to all six parties by the next election shows just how tough it has become at the top of Irish politics.