Failure to achieve a positive outcome to the Mitchell review would be "unforgivable as well as incomprehensible", Assembly member Mr Sean Farren told delegates during a debate on the Belfast Agreement.
Mr Farren said those responsible for failure would have a heavy charge to answer, after all the time and energy given to the review of the agreement by Senator George Mitchell, as well as the involvement and support of the Irish and British governments and President Clinton.
He said the answer to that charge "could only be that party interest had been put before the will and welfare of the overwhelming majority of the people of Ireland, North and South. An answer for which they would not easily, if ever, be forgiven."
Mr Farren, a senior party negotiator, was speaking in support of a motion by the SDLP's executive committee calling on the British and Irish governments as well as all the North's parties "to fulfil the wishes of the people and to implement in full the Good Friday agreement". The motion was carried.
Mr Farren said that neither decommissioning nor the establishment of the Assembly's executive was "a precondition, one for the other". Both were essential if the objectives of the agreement were to be achieved and this was the basis of his party's approach.
"The unionist position, `no guns, no government', is not a tenable position," he said. "Neither is it tenable to argue that every other aspect of the agreement must proceed, but that no understanding be given with respect to progress on decommissioning. We recognise that decommissioning is an important confidence-building measure and an essential part of the peace process.
"Without it, it would be very difficult to have confidence that the commitment to peaceful and democratic means made by all parties to the Belfast Agreement would actually mean what it says."
Mr Farren said the review had been clarifying the need to provide reassurances to all that progress could be made on these two vital parts of the agreement.
"These reassurances are key to a positive outcome to the review. Failure to achieve a positive outcome would be unforgivable as well as incomprehensible." Mr Farren said recent opinion polls continued to show that the vast majority of people in the North wanted the agreement to work. They had seen the benefits already flowing as a result of the stability and peace achieved so far.
"They desperately want the reassurance that it will last and that economic and social development can become the main items on the political agenda. In other words, they want to experience normal, democratic politics."
Mr Mark Durkan, seconding the motion, said for the review to succeed, the outcome would have to be the comprehensive implementation of the Belfast Agreement.
"That agreement, the whole agreement and nothing but the agreement. The review will succeed if it can deliver that," said Mr Durkan, who is also a senior party negotiator. He said it was clear that unionists needed a "real and reliable assurance that implementation is not going to be a decommissioning-free zone and is not intended to be a decommissioning-free zone. In the coming days, we need to look at how we can deliver that sense of real and reliable assurances."
Since the electorate voted for the agreement, it appeared to have been "somehow privatised into the hands of the Assembly and the parties and taken away from the people", he said. "It is time that we properly returned the agreement to public ownership and made the implementation of the agreement the key public business. And we can do that in the context of the review."
Mr Durkan said he believed the new institutions would "grind to a start" in the near future and the agreement would "take off in a very real and dynamic and vibrant way".
Politics since the agreement had been a "circle of frustration, what we need to do now is to create a circle of enablement".
Cllr Frank Feeley, from Newry, said responsibility for the failure to implement the agreement lay firmly with the Ulster Unionist Party and Sinn Fein.
He accused the UUP leader, Mr David Trimble, of "using the excuse of a divided party and shamelessly employing delaying tactics to avoid setting up the executive and making decisions he did not like".
Sinn Fein had avoided all decisions by "spinning, by hogging the media and by shadowboxing with reality. That reality is that Sinn Fein hasn't tried hard enough to persuade the IRA to make a statement that would help broker a deal."
Mr Feeley said it was necessary for Sinn Fein to start to work out a process by which decommissioning could take place.
Mr Peter Jones, a delegate from predominantly Protestant east Belfast, said even on that "stony ground", there were quite a lot of people who supported the Belfast Agreement. He called on the SDLP to reach out to the Protestant community and to go to east Belfast, perhaps on an election campaign, to listen to what people there had to say.