In just under 15 days, men and women on the island of Ireland will be asked to give their shared verdict on a matter of fundamental national importance - the Belfast Agreement.

The question put North and South will be different but the significance of the answer is identical. There has to be a Yes vote in both jurisdictions. It is politically essential that the margins and turnouts be such as to leave no room for doubt.

Of course, the agreement is a complex and lengthy document - tortuous in its negotiation and drafting. The detail is important but, in the end, the human choice of the voter will be simple. It is a choice between partnership and agreement on the one hand and division and conflict on the other.

There comes a point in any conflict where people realise that the status quo is no longer tenable; that there has to be change. Those changes can be excruciatingly difficult. Cherished principles and positions have to be evacuated to allow for a space where compromise and accommodation can be made.

Perversely, the certainties of conflict can create their own security. It took courage to go into uncharted political waters. The dynamic for change has its origins in the early 1990s. The working through of that logic of change has taken some considerable time to develop in the public and political psyche. Indeed, for some, it is not yet complete.

It is clear that there are aspects of the agreement which people find difficult. I respect those difficulties. Some feel that the sacrifices and pain of the past are being minimised and dishonoured. It is not easy for the bereaved to accept with equanimity the early release of prisoners. Indeed, it is overwhelming to see this forgiveness proffered by some relatives of victims. Profoundly demanding compromises had to be made by many people all along the route towards this agreement.

Let's recall the furore which surrounded the formulation of a common position between Hume, Adams and Reynolds. Many of us suspended our critical faculties at that time and took genuine risks with democratic principles for the sake of the peace process.

At this juncture, I would like to ask the rejectionists to look to the wider horizon. The final negotiations involved eight parties, two Governments, and independent chairmanship of outstanding calibre. They involved a huge intellectual and political investment. For those of us privileged to be there, no task was more important. The last two years of negotiation came after many years of painstaking preparatory work.

Is it a practical alternative to slip back into the morass of the last 30 years of misery and be viewed across the world as having missed the best opportunity for peace that we've had?

There are those who are tied to the old failed absolutism of the past. Tragically, there are some who are still using violence to express their views and it is heart-breaking that sectarian murders have occurred since the Good Friday agreement.

There are others who want the agreement to work but who have genuine qualms about elements of it. And, of course, even after the establishment of new institutions, there will be tensions and disagreements as is normal in politics. With goodwill and incremental trust, obstacles can be overcome.

In the first section of the agreement, participants commit themselves to basic principles including non-violence and partnership, equality and mutual respect. The agreement requires all to "work to ensure the success of each and every one of the arrangements to be established".

Surely, we all want a prosperous and peaceful and united Northern Ireland operating a partnership between both communities and those who see themselves as part of a third tradition.

For the first time, control over their own affairs and governance will be handed to all the people of the North. But it will be a Northern Ireland governance which will be the direct opposite of the old Stormont; an assembly devoid of domination by one side over the other. New constitutional and institutional arrangements have been agreed which are appropriate for all the people who live in Northern Ireland. Some reforms are wrongly represented as being partisan, such as those on policing. Surely it is in everybody's interests that, as the Presbyterian Church put it on Tuesday, "the composition, culture and style of policing should be reflective of and supportive of the diverse traditions of the people of Northern Ireland".

The North-South Council is about partnership. Politicians working together in this way will promote contact, understanding and trust. In time, I hope that unionists will reject the old stereotypes constantly peddled about the South and see us for what we are - a tolerant, economically vibrant and pluralist society. For our part, we must live up to this claim.

The agreement contains the essential elements of the partnership society whose creation was a founding goal for my party, the Progressive Democrats. The removal of the territorial claim in our Constitution, the principle of consent, and the creation of cross-community institutions in Northern Ireland, have been central to party policy on the North since our formation in 1985. The revised Articles 2 and 3 actually represent a modernisation of our basic values, not an abandonment of them. The new Article 3.1 expresses the aspiration to unity and establishes a mechanism to achieve it peacefully and by consent.

Whatever about the rejectionists, I cannot conceive of the sort of person who would not exercise their franchise on May 22nd - a day of truly historic significance in terms of representative democracy. Complacency is dangerous in a democracy. A simple majority Yes vote on May 22nd is not enough - everyone physically able to vote has a patriotic duty to do so.

On Good Friday, the whole country rejoiced in the agreement reached at Castle Buildings. On May 22nd, that patriotic fervour must be translated into a huge popular endorsement of this package. It's a chance to make our own history, and not be mesmerised by either the past or the future.

Liz O'Donnell is Minister of State at the Department of Foreign Affairs and Progressive Democrat TD for Dublin South.