The skill with which the SDLP always managed its relationship with political parties in the Republic contributed greatly to its success in steering Northern Ireland towards the goal of peace and stability during the years between its foundation in 1971 and the culmination of the peace process with the Belfast Agreement in 1998.
That party always worked closely with the government of the day in our State, while also maintaining friendly contact with whatever party or parties were in opposition.
In fairness, it has to be said that this potentially tricky relationship was helped by the substantial measure of bipartisanship sustained by our political parties, which was well maintained, except during the earlier period of Charles Haughey's leadership from 1980 to 1987, when the SDLP/Fianna Fáil relationship came under pressure on three issues.
The first of these arose in 1980 when Charles Haughey attempted to call off the campaign against the IRA in the United States, which had been initiated by John Hume in 1972 and carried on thereafter by the government and SDLP in parallel.
That was the only time when John Hume was moved to intervene directly in the politics of our State - supporting a public demand by Labour Party leader Frank Cluskey and myself that the taoiseach unequivocally dissociate himself from the IRA-supporting US organisations.
In the late 1970s, the SDLP had been attempting to make a subtle distinction between making their support for Irish unity conditional on Northern Ireland majority support and their opposition to what they described as the British guarantee on that issue. Latching on to this ambiguity also in 1980, Charles Haughey tried to persuade an SDLP delegation , but, joining his colleagues at a late stage in the meeting, John Hume managed to escape from that trap.
The third occasion on which a threat was posed to bipartisanship in our political system in a way that deeply disturbed the SDLP was when Charles Haughey opposed the 1985 Anglo-Irish Agreement and sent Brian Lenihan to the US on an anti-agreement mission.
But these three events were out of line with the bipartisanship on Northern Ireland that otherwise prevailed in the Republic's politics from the early 1970s onwards - which hugely facilitated the SDLP leader, John Hume, in his efforts to bring peace and stability to the North.
There was occasional co-operation between the SDLP at a local level and both Fianna Fáil and Fine Gael across the Border. In the 1970s, SDLP supporters from Armagh and Down helped Fianna Fáil in elections in Cavan-Monaghan, and in January 1986, following the mass resignation of unionist MPs in protest against the November 1985 Anglo-Irish Agreement, I instructed Fine Gael to help Seamus Mallon - both at local level and through the provision of technical assistance with research and polling - to win the Newry and Armagh seat at Westminster,
However, going back to a much earlier period, shortly before Eamon de Valera left Sinn Féin to form Fianna Fáil in 1925, he stood as an abstentionist republican candidate in what was then an eight-seat Co Down constituency - and, as there were only eight candidates, he was elected without a contest.
He did not stand again in 1929, after the abolition of PR in the North, but, most curiously, while president of the Executive Council of the Irish Free State, he successfully contested South Down in 1933 and for the following five years was a Fianna Fáil abstentionist member of the Northern Ireland parliament. However, he did not contest the subsequent 1938 Northern Ireland general election - perhaps because he was about to negotiate the agreement with the United Kingdom government that led to the return of the ports that had been retained as potential naval bases by the UK in 1921.
I do not believe these are good precedents for Fianna Fáil involving itself in Northern Ireland politics at this stage. The whole process of restoring peace and stability to Northern Ireland has depended for its success upon the constructive engagement of successive governments of different compositions in that process. And this depended on the fact that, none of the various government parties - Fianna Fáil, Fine Gael, Labour, Progressive Democrats or the now defunct Democratic Left - were directly involved in the Northern Ireland political scene.
Moreover, once Fianna Fáil felt able to join the other parties in our State in committing itself in the Downing Street declaration of December 1993 to the principle that reunification should take place only with the consent of a majority of the people of Northern Ireland, all subsequent governments found it possible to become accepted by the UUP, and latterly also by the DUP, as "honest brokers" in the evolving peace process.
If any party from the Republic involves itself directly in the political scene in the North, whether on its own or in conjunction with an existing Northern Ireland political party, this could, I believe, put at grave risk the future evolution of political relationships within our island.
There is a further crucial consideration which may not be currently appreciated by some politicians on either side of the Border. In any foreseeable future the only way in which the North can hope to break out of its sectarian political structure is through the emergence of the SDLP and UUP together as an opposition to the current dominant DUP/Sinn Féin alliance.
This may seem to some to be an improbable scenario - but in fact we have recently seen what could be the first sign of such a development, with representatives of each of these two parties attending each other's conferences, and with the emergence of a common approach by them to the issue of UDA funding.
There exists, moreover, a sociological basis for such a development. Northern Ireland is probably unique in today's Europe in being governed by a coalition of two basically working-class parties, the DUP and Sinn Féin. But the experience of recent decades throughout Europe suggests that in Northern Ireland the future may lie rather with parties more sensitive to and reflective of middle-class interests - so that over time the SDLP/UUP vote could grow at the expense of the DUP/Sinn Féin axis.
The involvement of a party or parties from the Republic in Northern Ireland politics might make it much more difficult for the UUP to ally itself with the SDLP - an alliance that offers what may be the only prospect of the emergence in Northern Ireland of a cross-community political system, and the end of sectarian politics.
Given that the whole history of the SDLP testifies to the value of that party remaining aloof from involvement in the party politics of the Republic, it would be surprising if these considerations did not weigh strongly with many members of that party.