The Taoiseach, Mr Ahern, has said the constitutional future of Northern Ireland relies entirely and exclusively on the principle of consent and that the British government has been "effectively ruled out of the equation".
The proposed changes in Articles 2 and 3 expressed "noble ideals" and declared openly "the desire for unity and the democratic, conciliatory and non-threatening spirit in which we wish to achieve it", he said.
Speaking at the 1916 Easter Rising Commemoration at Arbour Hill in Dublin yesterday, Mr Ahern said that in the reformulation of Articles 2 and 3, and in the Belfast Agreement, "it is the people of North and South who are sovereign and who share the territory of Ireland and its title deeds in all the diversity of their identities and traditions".
The Act of Union of 1801, in which kingdoms and parliaments were merged forever, had effectively been brought to an end between 1920 and 1921. The Belfast Agreement made this clear on the North's status.
"Its constitutional future, whatever about its past, will rest and rely entirely and exclusively upon the principle of consent. The British government are effectively out of the equation, and neither the British parliament nor people have any legal right under this agreement to impede the achievement of Irish unity if it had the consent of the people North and South, not that I believe the vast majority of British MPs or people would wish to do so," said Mr Ahern.
"Our nation is and always will be a 32-county nation. Antrim and Down are, and will remain, as much a part of Ireland as any Southern county. But we also recognise a plurality of traditions."
Mr Ahern said the new Articles 2 and 3 expressed noble ideals and strengthened, not weakened, the bonds that unite the Irish nation, North and South.
The new Article 3 borrowed some of the language formulated for the constitutional review committee of 1967 by Mr Sean Lamass, who took part in the 1916 Easter Rising.
This declared: "It is the firm will of the Irish nation, in harmony and friendship, to unite all the people who share the territory of the island of Ireland, in all the diversity of their identities and traditions, 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 on this island."
Addressing journalists after the ceremony, Mr Ahern said of recent sectarian murders in the North that it was inevitable that some elements would continue to attack the process. Recent murders had been "savage sectarian killings", but they must not be allowed to deflect the parties from the peace strategy.
Asked whether anyone who was convicted of the murder of Det Garda Jerry McCabe would be treated differently from paramilitary prisoners on the issue of prisoner release, Mr Ahern said that the case had not yet been heard.
However, reports of the time showed that the killing did not have the authorisation of a paramilitary group and this raised the question of whether it was a "criminal act", he said.
On the proposal that MPs elected in the North should be entitled to sit in the Dail, Mr Ahern said he was glad this was being considered by a joint Oireachtas committee on the Constitution.
During a memorial Mass in the Church of the Sacred Heart at Arbour Hill, Father Sean Kitt spoke of people's admiration of the "exhausting labours and noble dedication" of those involved in the peace process. He particularly praised Mr Ahern's courage and the work he put into the process at "a most difficult time".
The Mass was attended by 800 people, including members of the Cabinet and the Fianna Fail leadership. Among those there were the party's deputy leader and Minister for Public Enterprise, Ms O'Rourke, and the Minister for Foreign Affairs, Mr Andrews, and the co-chairman of the British-Irish Parliamentary Party Body, Mr Michael O'Kennedy.
Mr Ahern was applauded as he joined the parade to the memorial, led by the St James's Brass and Reed Band. The Proclamation of the Republic was read by Ms O'Rourke.
Of the 16 leaders of the 1916 Easter Rising, 14 are buried at Arbour Hill. Roger Casement was hanged in Britain and is buried at Glasnevin Cemetery in Dublin, while Eamonn Ceannt was shot and buried in Cork.