Former US president Bill Clinton believes it is a "miracle" that the Good Friday Agreement survived the Brexit process.
In an interview to be broadcast on RTÉ's Prime Time tonight, Mr Clinton, who was instrumental in negotiations to finalise the agreement, says Brexit was aimed at the heart of the Belfast Agreement.
"The idea that it [the Good Friday Agreement] weathered Brexit is a miracle, because Brexit was aimed right at the heart of the Good Friday Agreement, even if not intentionally... but it happened… so that's the way it was," he said. "But the peace held, the Irish peace held," he added.
Former first lady and former US Secretary of State, Hillary Clinton agreed.
She said Brexit has been an obstacle to restoring Stormont. "It's just that Brexit set it back, to be blunt, creating a very difficult situation for Northern Ireland in the midst of separating from the European Union," she said.
"That looks like it's on the way to being resolved, and hopefully it will be. And then the next step will be to stand up a government... There's a lot of work to be done in Northern Ireland to deal with the continuing challenges that face the people, and those who were elected should get about the business of doing that."
However, both the former president and first lady say that the fundamentals of the Good Friday Agreement are sound and will help the parties to find a way out of the current impasse.
Speaking to Miriam O'Callaghan in New York, Mr Clinton urged the Unionist community to engage.
"I think we should say, look there’s something to work with here. The party that’s getting the most votes now [Sinn Féin] doesn’t want to jam you, they want to work with you to resolve these things. How can we live together? How can we work together? How can we all put our heads on the pillow at night and feel at peace about what our children are going to face."
Mr Clinton also recalls the efforts of former Senator George Mitchell, who described his role in the negotiations as "the most onerous part-time job in history."
Three years earlier, then-President Clinton appointed him as his envoy to help broker peace in Northern Ireland.
Senator Mitchell had only agreed to take the job because he had been told it would not take up all his time.
Mr Clinton recalled their conversation towards the end of the negotiations.
"He said: 'You got me in to this part-time job. This is the most onerous part-time job in history.’ I said: 'George, you love it and so do I. Who do you want me to call?’ "
There followed a series of late-night and early-morning telephone calls between Mr Clinton and key players, including Gerry Adams, that are widely agreed to have helped secure agreement at the eleventh hour.
