The Minister for Foreign Affairs has castigated those who adopted a cynical response to Monday's announcement of a second round of IRA decommissioning.
Mr Cowen said this latest disarmament act was another important step towards the Belfast Agreement goal of replacing conflict and division with political engagement and partnership.
"Regrettably there was, as ever, a queue of those ready to diminish this achievement and to question the motivation of those who brought it about," he said in Ferbane, Co Offaly, last night on the eve of today's fourth calendar anniversary of the signing of the Good Friday accord.
"Their carping will not distract us from acknowledging the scale of what we have achieved together," he added.
Mr Cowen praised the work of Gen John de Chastelain's decommissioning body and paid particular tribute to the Ulster Unionist leader and First Minister, Mr David Trimble.
"There are far too many within the broader unionist community who have worked to undermine his position in a bid to undermine the agreement as a whole," he said.
"We have had our disagreements along the way - particularly about tactics and approaches - but David Trimble has stuck with the agreement and with his belief that if it was being implemented it would include a process of putting arms beyond use.
"The events of this week vindicate his commitment and vanquish the out-dated, out-of-step views of his opponents."
Mr Cowen said it was absolutely clear that a process of decommissioning was under way. "Some of the naysayers contend that the guns put aside were only museum pieces, but for weapons to be put beyond use they have to be useable.
"We have the Commission's word for it: real weapons, with deadly potential, have been taken out of the equation."
The Northern Secretary, Dr John Reid, yesterday denied that the IRA had disarmed in return for a secret deal to allow on-the-run republicans return to Northern Ireland free from the fear of prosecution.
"It is no secret that we want to deal with the issue of those prisoners who have been on the run," he said. "But we have to think of the victims. We have to think of the non-republicans who can't come back because of the threat from the paramilitaries."
A DUP delegation met Gen de Chastelain on Monday night, after which the Rev Ian Paisley said the decommissioning was designed to help Sinn Féin electorally in the general election.
He added: "Asked what he meant by the term 'substantial' the general claimed it could mean different things to different people."
Dr Paisley also said that the general could not be certain that the IRA was engaged in a decommissioning process.
Meanwhile Mr Mark Durkan, the SDLP Deputy First Minister, said the Good Friday agreement had transformed Northern Ireland on a scale few would have thought possible.
"We are now building the new partnership politics that the SDLP has advocated ever since our foundation," he said.
"By working together we hope to break down the divisions and distrust in our society and on our island. Our ultimate goal must be the unity of Ireland. A unity of people. A unity of prosperity. A unity of peace," he added.