Failure to grasp the current opportunity in Northern Ireland would be devastating, Senator Edward Kennedy has said. "History will harshly judge any who fail the test and waste the decisive moment."
Mr Kennedy was giving the Tip O'Neill Memorial Lecture in Derry in honour of the late speaker of the US House of Representatives.
"Many people have already taken risks for peace. John Hume laid the groundwork over many years for the current progress, and is one of the shining apostles of non-violence in our century.
"Gerry Adams and Martin McGuinness impressively led the way to the IRA ceasefire in 1994 and its restoration last summer. David Trimble demonstrated genuine leadership in bringing the Ulster Unionist Party to the peace table. John Alderdice deserves credit for his efforts to bridge the gap between the two communities.
"The representatives of the loyalist paramilitaries - David Irvine, Gary McMichael and others - helped achieve the loyalist ceasefire and have made ceaseless efforts to maintain it.
"The Women's Coalition deserves admiration and support for participating and persevering, and for demonstrating anew the rightful place of women at the highest level of politics.
"The governments of Bertie Ahern and Tony Blair have carried the process forward with skill and wisdom. Mo Mowlam is tireless in her commitment as evidenced by her unprecedented decision to meet with the prisoners in the Maze today. George Mitchell's transatlantic shuttle diplomacy is America's special gift to the peace process, living daily proof that the United States not only cares but can be scrupulously even-handed.
"John de Chastelain and Harri Holkeri deserve credit for their leadership and patience. And numerous others - church leaders such as Father Alex Reid and the Rev Roy Magee, community workers such as Geraldine McAteer and Jackie Redpath - have worked together hard and well to build bridges."
He continued: "There are some who seek to wreck the peace process. They are blinded by fear of a future they cannot imagine, a future in which respect for differences is a healing and unifying force. They are driven by an anger that holds no respect for life, even for the lives of children.
"But a new spirit of hope is gaining momentum. It can banish the fear that blinds. It can conquer the anger that fuels the merchants of violence. We are building an irresistible force that can make the immovable object move."
Mr Kennedy said there must be no return to violence. "Killing produces only more killing. Endless escalating cycles of violence, death and devastation have brought unspeakable human tragedy, deeper divisions between and within the two great traditions, and painful stagnation and failed prosperity for Northern Ireland."
He said that the present must learn from the past. "Equality and mutual respect are the twin pillars of peace. It is clear that the nationalist community will never accept a role of subservience to unionism. And the unionist community will never accept a role of subservience to nationalism.
"The obvious and inescapable conclusion is that these two traditions can find a stable relationship only on a basis of equality and mutual respect. A successful outcome must mean no second-class citizens on this island, and no second-class traditions either.
"The peace process does not mean asking unionists or nationalists to change or discard their identity and aspirations. It means using democratic methods, not bombs and bullets, to resolve the inevitable differences and tensions between them."
He continued: "I appeal to the talks participants to ask nothing for their own side they are not prepared to grant to the other, and to ask nothing from the other side they would not accept for their own. Let us make that principle the golden rule for the road to peace, to do unto others as we would have them do unto us."