The agreement was reached between the British and Irish governments and eight political parties or groups in Northern Ireland. Three were representative of unionism: the Ulster Unionist Party, which had led Unionism in Ulster since the early twentieth century, and two smaller parties linked to loyalist paramilitaries, the Progressive Unionist Party (associated with the Ulster Volunteer Force (UVF) and the Ulster Democratic Party (the political wing of the Ulster Defence Association (UDA)). Two of them have generally been described as nationalists: the Social Democratic and Labour Party and Sinn Féin, the Republican Party associated with the Commissional Irish Republican Army.   Regardless of these rival traditions, there were two other rallying parties, the Alliance Inter-communal party and the Northern Ireland Women`s Coalition. There was also the Labour Coalition. U.S. Senator George J. Mitchell was sent by U.S. President Bill Clinton to lead discussions between the parties and groups.  16 As a form of non-majority democracy, the aim of the Conjugian power-sharing institutions, founded after 1998 in Northern Ireland, was to allow representatives of each Community to integrate into local decision-making institutions without giving excessive powers to the majority19. mutual veto, proportionality and segment autonomy. Voters in Northern Ireland choose their MLAs according to a non-majority system, the single transferable Vote (STV).
Members of the Northern Ireland Assembly are registered as unionist, nationalist or Other. Ministerial posts within the executive are distributed in a strictly proportional manner according to the distribution of seats by the parties in the Assembly according to the D`Hondt method, so that each community has a certain number of ministerial posts proportional to the influence of its group and parties in the Assembly. In Concern`s petition procedure, each nominating group in the Assembly has the power to block any legislative act, making it mandatory to vote on a bill by a weighted majority of at least 60% of mlAs, including 40% in each nomination group, which amounts to a mutual veto. The two main political parties in the deal were the Ulster Unionist Party (UUP), led by David Trimble, and the Social Democratic and Labour Party (SDLP) led by John Hume. The two leaders together won the Nobel Peace Prize in 1998. The other parties involved in a deal 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 deal. It left the talks when Sinn Féin and loyalist parties joined because republican and loyalist paramilitary weapons had not been downgraded. The main problems that Sunningdale omitted and addressed in the Belfast Agreement are the principle of self-determination, the recognition of both national identities, Anglo-Irish intergovernmental cooperation and legal procedures to make power-sharing compulsory, such as inter-municipal voting and the D`Hondt system for appointing ministers for the executive.   Tommy McKearney, a former IRA member and journalist, argues that the main difference is the British government`s intention to negotiate a comprehensive agreement by involving the IRA and the more intransigent unionists.  With regard to the right to self-determination, the jurist Austen Morgan cites two qualifications.
Firstly, the transfer of territories from one State to another must be done through an international agreement between the British and Irish Governments. Secondly, the people of Northern Ireland can no longer bring a united Ireland alone; they need not only the Irish Government, but also the citizens of their neighbouring country, Ireland, to support unity. .