The agreement came after many years of complex discussions, proposals and compromises. A lot of people have made a great contribution. Tony Blair and Bertie Ahern were the leaders of the United Kingdom and the Republic of Ireland at the time. The presidency was chaired by U.S. Special Envoy George Mitchell.  The main themes addressed by Sunningdale and dealt with in the Belfast Agreement are the principle of self-determination, the recognition of the two national identities, Anglo-Irish intergovernmental cooperation and legal power-sharing procedures, such as inter-community voting and the D`Hondt system for appointing ministers to the executive.   Former IRA member and journalist Tommy McKearney says the main difference is the British government`s intention to negotiate a comprehensive agreement including the IRA and the most intransigent unionists.  With regard to the right to self-determination, two qualifications are recorded by the writer Austen Morgan. First, the transfer of territory from one state to another must be done through an international agreement between the British and Irish governments. Second, the population of Northern Ireland can no longer be alone in united Ireland; They need not only the Irish government, but also the people of their neighbouring country, Ireland, to support unity. Mr Morgan also pointed out that, unlike the Irish Act 1949 and the Northern Ireland Constitution Act 1973, drawn up under Sunningdale, the 1998 agreement and the resulting British legislation explicitly provide for the possibility of a unified Ireland.
 The conference takes place in the form of regular and frequent meetings between British and Irish ministers to promote cooperation between the two governments at all levels. On issues not left to Northern Ireland, the Irish government can present views and proposals. All decisions of the Conference are taken by mutual agreement between the two governments and the two governments, in order to make resolute efforts to resolve the differences between them. The two main political parties in the agreement were the Ulster Unionist Party (UUP), led by David Trimble, and the Social Democratic and Labour Party (SDLP), led by John Hume. The two heads of state and government together won the Nobel Peace Prize in 1998. The other parties to the agreement were Sinn Féin, the Alliance Party and the Progressive Unionist Party. The Democratic Unionist Party (DUP), which later became the largest Unionist party, did not support the agreement.