The SDLP leader, in the face of unionist cynicism and criticism, said he believed the IRA ceasefire was genuine and that it would be sustained. Mr John Hume said the talks must continue even if some unionists withdrew from the process.
Mr Hume said the British Prime Minister, Mr Tony Blair, had "rationally and reasonably" set out the terms for Sinn Fein's entry to the talks which opened the way for a new IRA ceasefire.
He repeated that allowing Sinn Fein into talks threatened no one: "What it is doing is creating a totally peaceful atmosphere in which dialogue for real agreement among our divided people can take place, and that agreement must have the agreement of both traditions. That does not threaten any section of our people."
Some unionists, Mr Hume complained in a number of weekend interviews, conveyed the impression that they would have preferred if there had been no IRA cessation. They seemed to be more comfortable with "politics that they can be against".
He criticised the "negative" response from unionists and said all parties should now be prepared to engage with a process that was non-threatening and saving human life.
Mr Hume indicated that the former British prime minister, Mr John Major, had last year rejected his proposals which Mr Blair now accepted.
It was those proposals, including the commitment that the decommissioning issue would not be a block to talks, which were sufficient to persuade the IRA to restore its ceasefire, he suggested.
The SDLP leader urged all unionist parties to remain in the talks, but added that the talks should proceed even if parties such as the DUP, the UK Unionists and possibly the Ulster Unionist Party abandoned them.
"I would be suggesting strongly that the talks process should continue with the door opened for people to return who have left, because at the end of the day no solution will be imposed on the people.
"The final decision on any agreement will be taken by the people through a referendum. So therefore there is no reason whatsoever for political parties to pull out of the talks," he said.
"It will not say much for the political leadership of parties who pull out of the talks," Mr Hume added. He was dismissive of unionists who said the British government had caved in to the IRA and Sinn Fein on the decommissioning issue.
"What really matters is the word of the IRA - when they say they have stopped do they mean it? If they were playing games, they could hand over a thousand guns on Monday and buy a thousand more on Tuesday.
"And even if they handed in a thousand guns tomorrow there are certain unionist political leaders who will say, 'How do we know they have handed in all their guns?'," he added.
Mr Hume said there was now a great opportunity for a lasting political settlement and all parties, including the unionists whatever their misgivings, should participate in the process.
