During the last 16 years nationalist representation on district councils in Northern Ireland has grown from 29 per cent to just under 40 per cent. Two quite separate factors have contributed to this growth. One has been the growth in the Catholic proportion of the Northern Ireland population, reflecting a combination of a higher Catholic birth rate up to the 1990s and the much lower proportion of Catholics going to higher education in Britain, from which about three-quarters of the graduates do not return.
However, a careful examination of the available demographic data suggests this probably accounted for less than half of the increase in the nationalist vote during this period.
The bulk of the increase has reflected the fact that the turnout of Catholic voters has steadily grown during this period. The 29 per cent of seats won by nationalist candidates in the district elections of 1985 reflected widespread abstention by Catholic voters, even though it was in that election that Sinn Fein made its entry into democratic local politics in Northern Ireland.
Only about one-third of the jump in the nationalist share of seats from 35 per cent to 39.5 per cent within the past four years is explicable by the demographic shift in favour of Catholic voters in the Northern electorate. The great bulk of the increase in the nationalist vote was accounted for by a higher turnout of Catholic voters, which mainly benefited Sinn Fein. There was also a small shift of previous SDLP voters to Sinn Fein, but this would have accounted for only a minimal part of Sinn Fein's gain in seats.
Despite the increased turnout of Catholic voters, even today the nationalist share of district council seats remains below their share of the electorate.
This is largely explained by the fact that in areas with large Protestant majorities, even with PR, nationalist candidates fail to secure the number of seats their share of the electorate would warrant. This is true of all nine council areas where the Protestant share of the vote is 70 per cent or higher.
Overall, I estimate this cost the nationalist parties about 10 to 12 seats, reducing their representation below 40 per cent, despite the fact that their share of the adult population is now 42 per cent, or perhaps even 43 per cent.
Curiously, the same pattern does not operate in predominantly Catholic areas where Protestant voters are now represented in most on a scale proportionate to their electoral strength.
The strengthening of Sinn Fein's electoral position, gaining four of the seven nationalist seats at Westminster, has vindicated the move away from violence and towards a democratic approach initiated eight years ago by Mr Gerry Adams, Mr Martin McGuinness and others.
Those of us in the Republic who for 30 years have supported the democratic and peaceful approach of the SDLP and have consistently rejected the violence of the IRA may regret this shift in Northern nationalist opinion. But undoubtedly this has greatly strengthened the hands of the Sinn Fein leadership in dealing with their hardliners. They are now better placed than ever to deliver on decommissioning.
If, as seems likely, the British government is prepared to deliver on the few policing issues left over from Mr Peter Mandelson's ham-fisted mishandling of the Patten Commission report, and on some further demilitarisation issues discussed with the parties at Hillsborough some time ago, the Sinn Fein leadership will have no excuse to back off on decommissioning in the forthcoming talks. And statements by Mr McGuinness and Mr Mitchel McLaughlin after the recent election offer some encouragement that there will be a positive response of this kind to further British moves.
It is true that there have also been some counter-indications to this, suggesting that Sinn Fein's electoral victory might have prompted a triumphalist and more hardline reaction. But given the exceptional political skill that the Sinn Fein leadership has hitherto demonstrated, it seems unlikely that they would want to destroy their credibility by backing away at this crucial point.
Whatever about hardline elements in the rank and file, the leadership must surely recognise that the acceptance of, and indeed support for, their peace initiative in this State, and also among moderate nationalist opinion in the North, has been predicated on a belief that they have been sincere in relation to decommissioning, and, in Mr Gerry Adams's recent words, envisaging the disappearance of the IRA.
Many of us supported their peace process from the outset because we believed it was seriously intended, although in view of past events, North and South, we did not find it easy to take and through many vicissitudes to hold to that stance.
We were prepared to accept many ambiguities and much stalling, and to close our eyes for a period to continuing brutality and intimidation, in the belief that, at the end of the day, Sinn Fein would deliver.
By any possible standards, the time for delivery has arrived. If in the next couple of weeks the re-elected British government plays its part, Sinn Fein must respond. I am sure that its leadership understands this.
gfitzgerald@irish-times.ie