One of the most important changes relating to Northern Ireland over the past 30 years has been the acceptance of the consent principle by all the political parties in the Republic, the Tanaiste has said.
At the Northern Ireland Economic Conference in Ballymena, Co Antrim, yesterday, Ms Harney said: "In 1968, few in the South accepted the right of the majority up here to determine the constitutional future of Northern Ireland. In 1998, every political party in the South accepts that principle."
Ms Harney recognised that change for people in the North would be more difficult. "Those who have lost loved ones during the Troubles will find it hard to forgive and impossible to forget.
". . . But the people of Northern Ireland must recognise that the past provides no path to the future.
"In this respect, it is heartening to see the way in which politicians from all sides, some of them formerly sworn enemies, are now working together to build a new future for Northern Ireland."
Ms Harney said a tremendous opportunity for peace existed. "The Good Friday Agreement created the structures for a new political beginning in Northern Ireland - a new assembly, new institutions, new ministries.
"Worked properly, these structures can deliver a great deal for the people of Northern Ireland." She added, however, that politicians at Stormont could deliver little if a culture of sectarianism still pervaded Northern society.
"Northern Ireland can continue with this kind of apartheid society, but is that what is wanted by all those hundreds of thousands of ordinary people who voted so recently in support of the Good Friday Agreement? I don't think so."