A new demographic reality has emerged from the latest census, with thetwo communities now roughly equal in size, writes Mark Durkan.
Yesterday's census paints a picture of change in the North. Terms like "minority community" and "majority community" - always inappropriate - are now irrelevant. A new demographic reality has expressed itself with two communities roughly equal in size.
These changes may cause concern to some, but they should come as a surprise to none. The reality is that the Catholic community has been growing steadily in size for decades. Another reality is that the nationalist vote in elections has grown with it.
All this has led to speculation about the imminence or otherwise of a united Ireland. The truth is that these figures make a united Ireland neither a "never" nor "inevitable".
What we can say with certainty is that if a majority votes in favour of a united Ireland - and the South agrees - then there must be one. That is what the Belfast Agreement says. As the party that did more than any other to negotiate the agreement, the SDLP is more determined than any other not to renegotiate it.
As with so much else in the agreement, Jeffrey Donaldson has difficulty accepting this. He demands a unionist veto on a united Ireland, but he cannot have it both ways.
Jeffrey and his mentor, Jim Molyneaux, have always stressed that the North must stay part of the UK for so long as "the greater number" wants it. Jeffrey must equally accept that the North will become part of a united Ireland if a majority wants it. There can be no higher threshold for consenting to a united Ireland than for consenting to the United Kingdom.
Just as the SDLP is clear that unity can be achieved under the agreement, we are also clear that unity must not undo the agreement. Whatever changes the future brings, some things will remain the same. We will still need to find a way of sharing our society as partners, we will still have to find a way of respecting each other as equals. Census politics will not alter the need for consensus institutions of government.
We have already mapped that way out in the Good Friday agreement and we see no reason why in a united Ireland we would alter its fundamental principles of "partnership, equality and mutual respect as the basis of relationships within Northern Ireland, between North and South and between these islands".
Our vision of unity is based on equality. We know that the domination of one tradition over the other did not serve us well in the past and recognise that it will not serve us well in the future. That is why we believe that the exact same guarantees sought by nationalists within today's Northern Ireland must equally be afforded to unionists within a united Ireland of tomorrow.
If majorities vote for unity North and South, then the North would become part of a sovereign Irish state. But the Assembly, with its cross-community protections, would continue. The Executive would continue, British-Irish co-operation would continue. All this would happen in the transformed context of a united Ireland. So, Northern politicians would no longer sit on the sidelines at Westminster, instead, they would have real power in a new Irish national parliament and in a new Irish national government.
Doubtless, adjustments to the agreement's structures to take account of unity would be required, but those adjustments would be made in the exact same way as adjustments to the agreement can be made today - only by agreement in a review.
That is the cast-iron guarantee to nationalists and unionists alike that their interests will be protected whatever the constitutional status.
Some nationalists argue against our vision of unity. They call instead for unionists to sit down with them and negotiate the future shape of a united Ireland. This may be an attractive slogan, but it is a defective strategy. There is no chance that unionists will negotiate a united Ireland before a referendum and there is every chance that in such a referendum, many voters will be afraid to forgo a United Kingdom with the agreement in favour of an uncertain united Ireland without the agreement.
By contrast, our vision of unity is not only fair and workable, it is achievable, because it gives unionists the reassurance that unity is not about the entrapment of a new minority and because it gives the South the reassurance of stability. Above all, it gives voters the reassurance that unity does not mean constitutional uncertainty. They are voting for the agreement and for Irish unity.
Achieving unity in the near future will require the persuasion of some unionists and reassurance of many others. Because of our unblemished record of peace and partnership and our unqualified commitment to the agreement, only the SDLP can persuade and reassure, only the SDLP can truly unite the people of Ireland.
But we are realistic. We know that this work will take time. In the meantime, even if our vision does not change unionist attitudes to unity, it should at least change unionist attitudes to the agreement. It should demonstrate that it is not temporary, transitional or tactical. Rather it is a covenant of honour between the two great traditions on this island that will withstand constitutional change.
In return for offering this covenant of honour, I ask that unionists think again about where those who want to collapse the agreement are leading them. They need to learn from history that every time that they have rejected accommodation, they have only narrowed their own options. Forgoing the agreement would be for unionists not only to lose their say in the Northern Ireland of today - but also their guaranteed position in a united Ireland of tomorrow.
I also ask the republican movement to reflect. The only viable path to unity is through the agreement. Republican activity has put unionists off the agreement - never mind deepening their fears of unity. The greatest contribution that the republican movement could therefore make to both the agreement and to unity would be to cease all illegal and untoward activity now and for good.
The Forum for Peace and Reconciliation should hold its next meeting next month. It is open to all the Irish parties from all parts of the island. At the forum, the SDLP will seek the endorsement of all parties of our vision and our values, to unify all of the people of Ireland through the agreement, to achieve Irish unity based on the agreement. Peacefully, democratically and by consent.
Mark Durkan, MLA, is leader of the SDLP