Hillary Clinton has warned that politicians in Northern Ireland must reach right down to the grassroots, delivering for families and the poor, if peace is to flourish.
During a one-day visit to Belfast, the US Secretary of State, one of the world's most powerful women, said: "Peace is always a work in progress and we have to do more to get out of the ballrooms, out of Stormont into the communities where people live where there is yet not that sense of lasting hope and optimism."
She delivered her cautionary advice in the ballroom of Belfast's £90m Titanic centre to 500 guests who included the First and deputy first ministers. Outside, violence and intimidation was mounting.
She pointed out that one of the guests, Naomi Long, the Alliance MP for East Belfast, had received a death threat. Mrs Long had been warned by police to keep away from her home and her constituency office as part of the loyalist campaign against Alliance's role in reducing the number of days on which flags were flown at Belfast City Hall.
Mrs Clinton had already met privately with Mrs Long to offer her solidarity, according to US diplomatic sources.
"Despite how hardy the peace has been there are still those who will not only test but try to destroy it. I really commend the leaders and citizens from the many groups who have condemned this violence and of course I join them in condemning it as well," Mrs Clinton said.
She also suggested that the feeding ground for violence lay in areas where people felt peace was not delivering to them.
"We have to continue to make sure that the promise of peace is delivered on because the progress in a democracy can never be taken for granted," she added.
"We know that we are suffering in a terrible economic downturn and I think that it is important to recognise that there has to be an economic return on peace, especially for democracies that have to deliver results for people," she said.
Mrs Clinton, whose key role in the peace process was praised by both Martin McGuinness and Peter Robinson, pledged that she would continue to support it when she steps down from her present post in January. It is widely anticipated that she will then run for the White House in 2016.
"Peace has to affect families. Families have to believe that life will be better for themselves and their children. I want to offer a cautionary word because if we do not focus on the community level, and as David Trimble [the former UUP leader and Noble Laureate] said to me earlier today (Sat), at the interface, we will not really achieve the peace that has been worked for," she stated.
She added: "I am looking for new ideas about how to help you do just that," and gave the examples of "the young man from a loyalist community whose father couldn't find work and sees his own chances slipping away or the young woman from a republican family who had to give up the idea of going to university" as the sort of people politicians must reach out.
Mrs Clinton said she intends to return to Northern Ireland as a private citizen and to assist with fundraising in the US. She ignored hints by Mr McGuinness and Mr Robinson that she should stand for the Presidency.
Earlier, when she met the two men at Stormont Castle, she strongly condemned recent violence. "There can be no place in the new Northern Ireland for any violence," she said.
"The violence is a reminder that, although much progress has been made, the hard work of reconciliation and fostering mutual understanding must continue," she insisted.