The former peace talks chairman, US Sen George Mitchell, has called on people and politicians in the North to hold their nerve despite the difficulties facing the peace process.
Speaking ahead of crisis talks between the North's pro-agreement parties and the two governments on Thursday, Mr Mitchell said people had to be "patient, steady and forward-looking".
"I think it is unrealistic to expect that difficulties and divisions that have built up over many decades, even centuries, are going to vanish with the stroke of a pen or in a short period of time.
"I think that the political leaders are struggling to keep this process together and persuade people that, however unpleasant the current situation, it is much better than the alternative. I think that is the view that ought to and will ultimately prevail," he said.
Mr Mitchell was back in Belfast yesterday to announce a postgraduate fellowship at a US university for local students. As chancellor of Queen's University Belfast, he was the keynote speaker at a graduation ceremony and also met a number of political leaders.
After briefing Mr Mitchell on the political situation, the SDLP leader, Mr Mark Durkan, said his party was grateful for the support the US administration had given it on the policing issue.
"George Mitchell is always a welcome visitor to our shores. Having done so much to help us get the agreement it would be an outrage if now we were to let paramilitary wrongdoing and political posturing to put the institutions in jeopardy. The United States helped us to negotiate the agreement. As repayment we must all prove that we are capable and worthy of making it work," he said.
Sinn Féin president Mr Gerry Adams also met Mr Mitchell. Mr Adams said he had pointed out both the problems facing the peace process and its achievements, adding: "You cannot take this process for granted. Neither should we underestimate the work that should be done collectively nor be complacent."