The former chairman of the Stormont talks, Mr George Mitchell, has made an impassioned plea to Northern politicians to implement the Belfast Agreement, especially after the "brutal murder" of Ms Rosemary Nelson.
Speaking in New York where he received the Irish-American of the Year Award from Irish America magazine, Mr Mitchell said the North's political leaders had "the awesome responsibility of life or death" in the current situation.
Last Good Friday, Northern politicians had shown the world "the true meaning of political courage" and everyone could take heart. "But as we knew then, and as we have come to understand even more clearly since, the agreement does not by itself provide or guarantee peace or political stability or reconciliation. It makes all of those objectives possible, but if they are to be achieved much more remains to be done.
"The events of recent weeks, the difficulty in fully implementing the agreement, make clear how huge are the obstacles to a durable and sustainable peace in Northern Ireland. The terrible tragedy, the brutal murder, of Rosemary Nelson reminds us again that there are those in Northern Ireland, as there are in every society, who will act with savagery and without restraint to attain their ends.
"What we must do now is to redouble our efforts, redouble our support and our encouragement for those who are still engaged in the difficult process of making peace in Northern Ireland. It is not easy. I spent 15 years in the US Senate, six of them as majority leader, I went through many difficult political battles, but nothing we faced was like the difficulty that faces the political leaders of Northern Ireland.
"It is not just their careers that are at risk, it is their very lives and the safety and security of their families. We must be understanding, we must be patient, we must be tolerant, but we must also be insistent and we must say to those leaders: `You have done much but you must do more'.
"History might have forgiven the failure to get an agreement, given the difficulty of all the previous efforts to get a lasting agreement, but history will not be forgiving if an agreement, once reached, is not implemented.
"There is no political advantage that is worth even a single life and surely no political advantage that can be worth the risk of plunging Northern Ireland once again into the cauldron of sectarian violence and the war that raged there for so many years."
The overwhelming majority in Northern Ireland wanted peace and reconciliation. "We must do all we can to see to it that they have that kind of life, especially young children in generations to come.
"In just a few weeks we will mark the one-year anniversary of the Good Friday agreement. I implore the political leaders of Northern Ireland: you must regard implementing the agreement with all the urgency, all of the importance, all of the energy that you regarded getting the agreement in the first place, indeed even more so for the reasons I have stated earlier."
Mr Mitchell's sentiments were echoed in a video message from President Clinton, who said: "Now it is up to all the parties to complete the work for peace, acting in a spirit of compromise and with the kind of determination that George Mitchell has always shown."
The awards ceremony at New York's Plaza Hotel was also attended by Senator Edward Kennedy; the Minister for Defence, Mr Smith; the US ambassador to Ireland, Mr Mike Sullivan; Ms Bairbre de Brun, of Sinn Fein; Mr Gary McMichael, of the Ulster Democratic Party; the leader of the Northern Ireland Unionist Party, Mr Cedric Wilson; Mr Louis Belton TD (Fine Gael); Mr Chris McGimpsey, of the Ulster Unionist Party; the president of John Jay College and member of the Patten Commission on Policing, Dr Gerald Lynch; the businessman Mr Donald Trump; the director of the US Peace Corps, Mr Mark Gearan; Ms Trina Vargo, of the US-Ireland Alliance; and the authors Frank and Malachy McCourt.