The Democratic Unionist Party is a hardline Unionist party in Northern Ireland led by Ian Paisley. It is the largest unionist party at both the Northern Ireland Assembly level and in the Westminster Parliament.
Established in the 1970s by Ian Paisley, it evolved from the Protestant Unionist Party. It does not and has never had any Catholic members, unlike the smaller Ulster Unionist Party. It has won seats at local council, province, national and European level; Paisley was elected one of Northern Ireland's three European Parliament members (MEPs) at the first elections in 1979 and retained that seat in every European election until 2004, receiving the highest percentage popular vote of any Northern Ireland, Republic of Ireland or Great Britain MEP and one of the highest anywhere in Europe. In 2004 Paisley was replaced as the DUP MEP by Jim Allister.
The DUP also holds seats in the British House of Commons and has been elected to each of the Northern Ireland conventions and assemblies set up since the party's creation. It has long been the major rival to the other major unionist party, the Ulster Unionist Party (known for a time in the 1970s and 1980s as the Official Unionist Party (OUP) to distinguish it from the then multitude of other unionist partes, some set up by deposed former leaders).
The DUP were originally involved in the negotiations under former United States Senator George J. Mitchell that led to the Belfast Agreement (also known as the Good Friday Agreement on account of the day on which it was signed.) However the party withdrew in protest when Sinn Féin, a republican party with ties to the Irish Republican Army (IRA), was allowed to participate after the ceasefire. The DUP opposed the Agreement in the referendum that followed its signing, and which saw the Agreement approved reasonably comfortably nonetheless.
The DUP fought the resulting election to the Northern Ireland Assembly and took two seats in the multi-party power-sharing executive but while serving as ministers refused to sit in at meetings of the Executive Committee (cabinet) in protest at Sinn Fein's participation. The Executive ultimately was suspended over unionist unhappiness on the slow nature of IRA disarmament.
In the delayed Northern Ireland Assembly election of 2003 the DUP became the largest political party with 30 seats. In 2004 it became the largest Northern Ireland party in the Parliament of the United Kingdom, with the defection of Jeffrey Donaldson. On December 12, 2004, English MP Andrew Hunter took the DUP whip, giving the party 7 seats, in comparison to the UUP's 5, Sinn Fein's 4, and the SDLP's 3.
The DUP does not encourage Roman Catholic members.