Inside Politics:The Green Party has devised an ingenious solution to the problem of how its Ministers and TDs can back the Yes campaign on the Lisbon Treaty even if the party refuses to follow, writes Stephen Collins.
However, previous experience suggests that political manoeuvres to get around referendum difficulties have a habit of coming unstuck.
It has emerged in recent days that the Green leadership has devised a formula to deal with the impact of a decision by party members at a special conference in two weeks' time not to back the Yes campaign.
It is proposing a strategy whereby the Green Ministers would support a Yes vote, thus preserving collective cabinet responsibility, even if the party members decline to go along.
The strategy will be decided by a special conference in Dublin by party members who will be given three options on how to proceed.
They will be offered the choice of supporting the Yes campaign, the No campaign or the compromise of committing the TDs to backing the Government while allowing the party to stand aloof, with members supporting whichever side they wish.
A two-thirds majority is required for the adoption of any of the three motions. If the Yes side can muster two-thirds the leadership won't have a problem, and the party will simply back the Government campaign.
Conversely, if the No side can get the numbers the party will be committed to opposing the Government, but it will also be on the way out of office.
At this stage it appears that the compromise motion giving the members the flexibility to differ from their Ministers and TDs is the one most likely to command the required majority.
Its adoption would mark a new departure in Irish politics, but it would not be the first time that a referendum has posed a serious difficulty for a coalition government.
When Garret FitzGerald's Fine Gael/Labour government launched a referendum campaign to lift the constitutional ban on divorce in 1986 it had to find a formula to get around the fact that one senior minister, Patrick Cooney, was opposed to the measure and actually made an important intervention calling for a No vote.
To avoid a situation whereby Cooney would be obliged to resign for a breach of collective cabinet responsibility on an issue of conscience, the amendment to the Constitution was proposed not by the government as a collective entity but by "the parties in government". It was a formula that preserved the unity of the government.
This time around the exact reverse may apply, with "the parties in Government" failing to agree on a unified stance but the Government as a collective entity supporting the campaign for a Yes vote.
In 1992 the Progressive Democrats mixed both approaches when confronted with an unwanted referendum on the issue of abortion.
Albert Reynolds and Fianna Fáil were anxious to hold a three-stranded referendum to deal with the crisis caused by the X case. The PDs had no difficulty with the constitutional amendments relating to travel and information but opposed the plan by the senior government party for an amendment on the so-called "substantive issue" of abortion.
"It is my strongly-held view, and that of the Progressive Democrats, that inserting a new provision in the Constitution of Ireland is not the proper mechanism to attempt to regulate such exceptional situations," PD leader Des O'Malley told the Dáil in the debate on the referendum Bill.
However, at Cabinet the PDs did not try and block the amendment with which they disagreed, and in the Dáil the party TDs supported its passage despite reservations expressed by some of them.
In the campaign itself the party allowed all its members, including ministers and TDs, to take whichever side they wished on the government proposal. The amendment sought to maintain the ban on abortion except in cases where there was a threat to the life, as distinct to the health, of a mother.
The situation in 1992 was far more politically divisive than the current problems facing the Greens. The PD ministers made no secret of their opposition to their own government's amendment and, in any case, relations in cabinet had become poisonous by that stage.
There was a re-run of the "substantive issue" in 2002 during Bertie Ahern's first administration.
This time around PD leader Mary Harney backed the proposal, but backbench TD Fiona O'Malley said she was voting No and junior minister Liz O'Donnell refused to say how she would vote. Again the measure went down to defeat.
The lessons from 1986, 1992 and 2002 are ominous. In all three cases of divided views among coalition partners constitutional amendments proposed by the government were lost. The political ramifications were enormous in 1986 and 1992 but not so in 2002.
The loss of the divorce referendum fatally undermined the standing of the FitzGerald government and it went down to a thumping defeat in the general election of 1987.
In 1992 the political situation was even worse. The PDs pulled out of government before the referendum, on a different issue, leaving the party free to say what it liked. Fianna Fáil slumped to its worst result since 1927 in the general election, and the referendum on the "substantive issue" was lost.
The clear lesson is that divided views among the parties in government help to fuel No campaigns and in the longer run threaten the stability of the coalition.
This time around the Greens are in an awkward position because the party from top to bottom has campaigned for a No vote in the last five referendums on Europe, ranging from the Single European Act in 1987 to the Maastricht Treaty in 1992, the Amsterdam Treaty in 1998 and the two referendums on the Nice Treaty in 2001 and 2002.
It is this long experience of opposing EU treaties that has led to doubts about whether the members will agree by a two-thirds majority to back the Yes campaign. Although an even greater majority backed the move into Government, it is asking a lot of party members, weaned on a diet of negative conspiracy theories about the EU, to suddenly put their trust in it.
The compromise formula allowing members the flexibility to campaign for or against the amendment while the Ministers back the Yes campaign is probably the best way through the minefield for the Greens and their partners in Government.
Many other factors will influence the decision on whether the Lisbon Treaty is approved by the Irish people.
The primary responsibility rests with Fianna Fáil to enthuse its own supporters and get them to the polls to vote Yes, but if in the end the referendum is defeated there will be serious implications for all the parties in Government.