The nature and extent of the constitutional changes envisaged in the Northern Ireland Agreement are only now beginning to emerge. Voters in the Republic will be asked to endorse a total of six distinct amendments to the Constitution in the process of ratifying the agreement on May 22nd. The complexity of the changes, which far transcend the emotive proposal to delete the territorial claim to the North, obscure the many significant constitutional and legal implications which could follow.

Northern voters will, simultaneously, be asked to participate in a consultative referendum to support the agreement which, in the introduction of the principle of consent, will fundamentally alter Northern Ireland's constitutional relationship within the United Kingdom.

In the Republic's referendum in five weeks, it could validly be argued the mechanisms being used to enshrine the agreement in Irish law are of almost equal significance to the constitutional changes themselves.

Most voters know they will be asked to delete Articles 2 and 3 of the Constitution and replace them with newly worded Articles 2 and 3. The new Article 2 will confer the entitlement and birthright on every person born in the island of Ireland, which includes its islands and territorial seas, to be part of the Irish nation and, under law, a citizen of Ireland.

The new Article 3 contains the aspiration of the Irish nation to unite all its people, "recognising that a united Ireland shall be brought about only by peaceful means with the consent of a majority of the people, democratically expressed, in both jurisdictions". The Irish nation, in other words, will be defined by its people, not its territory.

Other important constitutional questions, with far-reaching implications, will also be put to the people. The Northern settlement will not be agreed unless all the amendments are passed.

Article 29 of the Constitution deals with the State's international relations. The third amendment to the Constitution on May 22nd asks voters to insert a new Section 7 into Article 29 to permit the State, in Section 7 (i), "to be bound by the British-Irish Agreement done at Belfast" on Good Friday.

This change is being effected in much the same way as membership of the then EEC, the Single European Act, the Maastricht Treaty and the proposed Amsterdam Treaty, were put to referendums. The Northern Ireland Agreement, however, will stand alone, separate from EU matters, in a special section of its own but having, lawyers say, similar direct legal effect within this jurisdiction.

The fourth amendment is contained in Section 7 (ii) of Article 29 to cover the devolution of powers to the North-South Ministerial Council and consequent implementation bodies. It provides that "any institution established by or under the Agreement may exercise the powers and functions thereby conferred on it in respect of all or any part of the island of Ireland . . ."

It is interesting to note the North-South institutions are receiving special mention in the Constitution, even though they are a component of, and already presumably covered by, the new Section 7 (i) ratifying the whole agreement.

The fifth amendment being put to voters on May 22nd proposes a new Article 29 (7) (iii), making all the constitutional changes conditional, most unusually, on a Government declaration that the Agreement has come into effect, the Assembly and the North-South bodies have been established simultaneously.

The Government is to be allowed 12 months from April 10th to make this declaration. Otherwise the Government may ask the Dail to extend the period by law, or the formal changes to Articles 2 and 3 will not be made.

The sixth amendment being put to voters proposes a new Section 8 of Article 29 saying: "The State may exercise extra-territorial jurisdiction in accordance with the generally recognised principles of international law". This is a newly-worked version of the existing Article 3 of the Constitution which declares that "pending the reintegration of the national territory" the laws enacted by the Oireachtas would have the like area and extent of application "as the laws of Saorstat Eireann and the like extra-territorial effect".

These six changes in the Constitution will be accompanied, on the British side, by the repeal of the Government of Ireland Act, 1920, and new legislation, the Agreement states, "relating to the constitutional status of Northern Ireland".

The new British act, which is "to have effect notwithstanding any other previous enactment", will enshrine the principle of consent in Northern Ireland. Northern Ireland in its entirety will remain part of the United Kingdom and shall not cease to be so without the consent of a majority of its people voting in a poll. Correspondingly, if it is the wish of a majority in such a poll to form part of a united Ireland, the Secretary of State will legislate for this.

The net effect of all of these changes, if accepted in the referendums, will be nothing short of revolutionary in constitutional terms, North and South.

The Union, as it stands in British constitutional terms, will be changed, changed utterly, by the Northern Ireland Agreement.

Parliament is sovereign and supreme, by British constitutional standards. The enshrining into British legislation of the principle of consent for Northern Ireland, however, will alter that. Northern Ireland will then have a unique status within the United Kingdom because the people will be sovereign.

The principle of consent which is, arguably, another way of expressing the principle of democratic self-determination, will permit the people, not the parliament, to decide Northern Ireland's future.

The recognition of the principle of consent in the Irish Constitution will also bring radical change to Northern Ireland's relationship with the Republic. The agreement will allow the Oireachtas, for the first time, to legislate for the devolution of powers inside Northern Ireland through the North-South bodies.

The amendment to allow the State to exercise extra-territorial powers will copperfasten this right in a much greater way than previously recognised by the courts.

The accompanying corollary of all these amendments, changing the constitutional basis of the Irish State and the remit of the Executive, suggests that they, and the Northern Ireland Agreement, must be amenable to the processes of the Irish courts.

If the Constitution, the Government and the Dail are to have a remit, albeit limited since it is not envisaged that the North-South structures themselves will legislate, then surely in Northern Ireland the courts can review such developments?

This question shows up one interesting flaw in the agreement itself. The governments and the parties have failed to put an independent body in place to regulate it.

There is another important point worth raising. It is being proposed in the referendum that the Northern Ireland Agreement will receive a status never accorded to the Anglo-Irish Agreement in 1985, by being expressly written into, and recognised by, the Constitution. Does this mean, in legal terms, that it can only be changed with the agreement of both governments? Or the people of Ireland, North and South?

The answer to these questions could cast a new light on the letter of comfort from the British Prime Minister, Mr Tony Blair, to the Ulster Unionist leader, Mr David Trimble, promising to introduce legislation if the decommissioning of arms is not carried out within a specified period. Can the agreement be unilaterally changed by British legislation after it is put to the people in a referendum in this State?

The approval of the agreement, North and South, on May 22nd, may resolve, finally, the legal dilemma which has existed since 1921 as to whether Ireland constitutionally was created by the British or by itself.