Northern Ireland had begun to emerge from the very dark shadows of the past, the Taoiseach, Mr Ahern, told the Dβil.
"The peace has not been perfect. But there are many, many more people alive today than would otherwise have been if we had not started this journey of peace. There has also been a resurgence of urban renewal programmes and increased economic activity and prosperity.
"The alternative is not to be contemplated. We have witnessed elsewhere in recent times the terrible consequences when momentum is lost and violence returns." Speaking during a debate on recent developments in the North, the Taoiseach said the republican movement had now taken the historic step necessary to give the peace process a new momentum.
"This development is of profound, historic importance and deserves a generous response." On policing, Mr Ahern said he believed they now had the conditions for the delivery of the spirit and substance of the Patten report. He hoped that, in time, Sinn FΘin would find it possible to participate and contribute to the new beginning in policing. "It is precisely at this time, as the new police service is developing, that they can make a particularly valuable contribution."
The Fine Gael leader, Mr Michael Noonan, said he had long been a critic of the republican movement in both its political and its military manifestations.
"In my first ministerial position as Minister for Justice, I found myself having to cope with the very fundamental challenge which the IRA posed, not just to peace and stability in Northern Ireland, but to the very foundations of this State.
"It is against this background that I now commend the courage which lies behind the statement issued by the IRA yesterday afternoon. I do not for one moment doubt the difficulties which yesterday's initiative has caused for the IRA, its volunteers and supporters.
"The IRA has put a quantity of arms, ammunition and explosives completely beyond use and this has been verified by the Independent International Commission. They have done so, in their words, 'to save the peace process and to persuade others of our genuine intentions'. I recognise the courage and generosity of their decision."
The Labour leader, Mr Ruair∅ Quinn, said the IRA could finally stand proud that they had, at last, begun to accede to the democratically expressed wishes of the people of Ireland, north and south.
"Some may say that the IRA were never party to the Good Friday agreement. But Sinn FΘin, their political wing, clearly were. And notwithstanding who did or did not negotiate the Good Friday agreement, all Irish people were duty bound to comply with its terms when it was endorsed by the Irish people.
"The IRA have no basis to exempt themselves from this principle, which binds us all. For the IRA, it is a case of better late than never." Loyalist paramilitaries, Mr Quinn added, now had a short window of opportunity to respond.
The Minister for Foreign Affairs, Mr Cowen, said the significance of Tuesday's events had been generously recognised by the vast majority of people on the islands.
"There are, alas, a small minority of siren voices who wish to degrade yesterday's achievement and to keep the issue open as a potential brake in the further outworking of the peace process.
"I fully share Prime Minister Blair's views in this regard - we must not let the wreckers or the cynics win. Those who seek to destroy the agreement by force or intimidation will be dealt with severely by the forces of law and order in both parts of the island."
Mr Albert Reynolds, a former Taoiseach, said the republican movement had made a bold and brave decision in taking this step forward.
The leader of the Green Party, Mr Trevor Sargent, said that for most people in Ireland, the day had been too slow in coming. "However, it would be wrong to forget the concerns of some who fear that this announcement may have come too soon."