The Democratic Unionist Party wants a veto on the operation of the Northern Ireland Executive, the leader of the SDLP, Mr Mark Durkan, has warned.
Offering a deeply pessimistic assessment of the prospects for an agreement in the weeks ahead, Mr Durkan said the DUP is seeking "minority rule".
The DUP's demands for executive accountability to the Assembly amounts to a demand for a future veto on the operation of ministers, he said. "It is clear that it isn't political accountability that they want, but party control. Their party's control," Mr Durkan said in Dublin.
"People are saying that they want this [ veto] but not to use it. They say, 'Trust us'. If they get their way with this, it means minority rule. And they will practise it. If they get the last word, then the last word will be 'No'. They say that they will not practise it. That is just a fig-leaf," he told the college's historical society.
"The DUP will not pass up a veto any more than Sinn Féin will pass up a photo-opportunity. I agree that minority rule is a bad thing, but that is what they are trying to do now." The DUP's refusal to agree to the joint election of the First Minister and Deputy First Minister is evidence of the way the party would behave if in power, he said.
The two top Ministers are meant "to be leaders in society", he said: "How can that be if they will not even appear together? That is not just ludicrous, it is actually dangerous."
The SDLP's suspicions about the DUP are not shared by the Irish and British governments, or at least not to the same extent.
Earlier, the Minister for Foreign Affairs, Mr Dermot Ahern, and the Northern Ireland Secretary of State, Mr Paul Murphy, offered cautious assessments.
In his Trinity debate speech, Mr Murphy said the Executive and the Assembly's suspension two years ago has been "an unbelievable travesty and a corruption of democracy".
"It is wrong that I have to take decisions on schools, decisions on the health service, transport, roads and education."
Paying tribute to the last Executive, he said: "Don't believe that they did not govern for everybody, because they did. They did the job. They did a better job that I am doing, or my ministers." Mr Murphy said the reason they did was because the parties were fully accountable to NI voters.
"I do not know whether we can make that deal. I can tell you that I think the parties are serious about wanting to make that happen. They are very serious about wanting to come back and govern Northern Ireland. I think we can overcome the difficulties. They are very hard," he said.
Following an Iveagh House meeting with Mr Murphy, Mr Ahern said a number of key issues, including decommissioning and the future of paramilitaries, were still outstanding. "We will make another effort over the coming days to try to pull them together," said Mr Ahern, who will meet an Ulster Unionist Party delegation today.
"There is a window of opportunity. This is accepted by everybody. We will be upbeat when the discussions are finished and successful. In the meantime we have to put the shoulder to the wheel. There is a tremendous amount of work going on in the background," said the Minister.
Asked if expectations of an agreement should be raised, Mr Murphy said: "The hope, the expectation should certainly be there." A "complete deadline" can never be put on negotiations, he said: "[ But] it is far better to deal with these issues now as quickly as we can.
"There is a mood of willingness and understanding out there amongst all of the parties," said Mr Murphy.