A former Clinton aide who played a key role in securing Sinn Fein leader Gerry Adams his first US visa has said it is time for a "generational shift" in the peace process.
Nancy Soderberg said the real change would come at least another generation after the conflict ended, but added Northern Ireland should be further along the road to compromise.
Stormont power-sharing stalled earlier this year following a dispute between the DUP and Sinn Fein over the botched Renewable Heat Incentive scheme. Negotiations will resume after the June 8 general election.
Ms Soderberg said: "By now, they should be further along and it is time to have a generational shift so that the leaders that take over are not so steeped in the past.
"It is very hard for the current leaders to compromise and move forward."
The foreign policy strategist was a former US deputy national security adviser who worked on the peace process during President Bill Clinton's first term in the 1990s. She added: "When I was involved in the early stages, it was the women and grass roots who demanded change and it will take them to step up and say let's move on. This society is still as divided as it was before, though not by violence, which is a major accomplishment."
She said peace was irreversible, but warned Brexit threw up new challenges.
Ms Soderberg was attending a conference in Armenia, the Aurora Humanitarian Initiative.
She said she always thought it would not matter whether Northern Ireland was part of Britain or Ireland because eventually integration of Europe would make that a non-issue.
"I never really thought it mattered as long as people had a chance at a prosperous life.
"I think that is what most people want, the chance of a good job, a good education, a good future for their kids," Ms Soderberg said.
She said it was hard for the current leaders to move forward.
"You never forget the past, but you don't want to be mired in the past and it is time to forge a more unified society where the peace walls come down and integration occurs and trust builds up on both sides, and that is going to take, usually it takes a generation or two - the real change is after two generations.
"It is up to the next generation to step up."