While many psychologists argue that people nowadays aren't truly 'adults' until they reach 25, for a political party it's an eternity to wait before joining the big boys' club and entering government.

The Progressive Democrats, for example, were barely out of nappies before they got their shot at power and the party has spent over half its 20-year existence sitting around the cabinet table. And Democratic Left got its place in the sun just a few short years after it broke with its Stickie (or should that be sticky? ) past, before going on to mount a successful reverse takeover of the Labour Party.

Perhaps understandably given its 'anti-party party' origins, the progress of the Greens has been more tortuous, notwithstanding its fine achievement in getting six TDs elected in 2002 and the undoubted success it has had in introducing the green agenda in mainstream politics. But that might be about to change. The way things are shaping up, the Green Party has a unique each-way chance of government after the next election . . . if it is bold enough to embrace the opportunity.

On the one hand, if the Fine Gael momentum of the past two years continues, a place in the Rainbow coalition beckons . . . there is simply no way that Fine Gael and Labour will have the numbers without the Greens to put together a government. But even if the Rainbow falls short of the numbers, a second, virtually ignored, option could potentially emerge in the shape of government with Fianna Fail and the PDs.

A detailed analysis of the 43 constituencies, conducted by the Sunday Tribune over Christmas, predicted that neither the current government nor the Rainbow parties would reach the magical 83-seat figure at the next election.

While many commentators have been pointing to the possibility of a Fianna Fail/Labour coalition in such a scenario, simple Dail mathematics point to the potential for the Greens to link with Fianna Fail and the PDs. The three parties combined could afford to drop 12 seats on their 1997 performance and still have an overall majority.

The prospect of coalescing with Fianna Fail and the PDs is likely to horrify the traditionalists in the Green movement. To them, Fianna Fail is the political version of the antiChrist, while the PDs are right-wing Thatcherites who are too close to big business.

But the 'realos' in the party will know that politics makes strange bedfellows . . .

remember how Fine Gael and Democratic Left got on like a house on fire in government? . . . and if the Greens are serious about implementing their agenda, then they would be unwise not to keep their options open.

Fianna Fail is notoriously malleable when it comes to negotiating coalition deals.

The PDs have shown how a small party can implement large chunks of its policy platform in coalition with Fianna Fail. And while it makes for good copy to knock the PDs' right-wing ethos, the Greens may have more in common with the likes of Fiona O'Malley and Liz O'Donnell in the PDs than they would care to admit.

If the mooted Rainbow government does have the numbers to form a government, then all will be fine. But if it doesn't, the Green Party could be faced with a stark choice: does it stick to its 'principles' and stay in splendid isolation/opposition, or does it get its hands dirty and get into government with Fianna Fail and the PDs with a view to actually implementing Green policies, instead of just talking about them?

The integrity of the six Green TDs is beyond question and one shouldn't underestimate the level of soul-searching involved in such a decision, but ultimately realpolitik is about getting into government.

To be fair to the party, it has shown an increasing awareness that it can adopt a pragmatic approach to the day-to-day business of politics without jettisoning its core values.

The party's decision not to embrace the FG/Labour Mullingar Pact is smart politics. Pat Rabbitte's hardline stance in ruling out government with Fianna Fail means there will be no repeat of the 2002 election, when there was no real alternative to the current government. That frees the Greens to concentrate on what is best for their party, and they quickly realised that they risked being reduced to bit players if they threw in their lot exclusively with Fine Gael and Labour at this point.

The decision of the party conference last year to extend the leader's term until after the next election, and not to make the ending of military stopovers at Shannon Airport a precondition for entering government, also shows that the party is acquiring a necessary hard-headedness.

Politics is a numbers game and the party needs at least to maintain its current Dail strength if it wants to shape the policy direction of the next government. If the party is to hold onto and possibly improve on its six seats, then it will have to show that it can do practical politics as well or better than the other parties.

That doesn't mean abandoning core Green values. The best way for the Greens to restrict fur farming or reduce Ireland's CO2 emissions is to get into government but, in order to do that, the party needs to be cute enough to realise that these issues are not going to turn on voters.

What matters to the main body of voters . . . even in leafy, urban constituencies such as Dun Laoghaire, Dublin South, and Dublin South East . . . are issues such childcare, transport, education, house prices and healthcare. They have to be the party's main focus in the run-up to the general election.

If the Greens do stay focused and resist the temptation to indulge in stunt politics . . . like chaining themselves to trees on O'Connell Street, holding up placards in the Dail or issuing press releases on Celebrity Big Brother . . . then they can face into the general election with good grounds for optimism.

The party has a real chance of holding its six seats. Trevor Sargent will certainly be returned, while John Gormley, Eamon Ryan, Dan Boyle and Paul Gogarty would be favoured to hold on. Ciaran Cuffe has a battle in Dun Laoghaire but, at worst, has a 50-50 chance of retaining the seat. Mary White in Carlow-Kilkenny is the Greens' best chance of a gain, although the party also has hopes in Wicklow and, possibly, Clare and Galway West.

A return of six or seven deputies would very possibly give the party a veto over who becomes Taoiseach and a place at the cabinet table. What better way to mark its 25th anniversary?