Unionist Pact in Northern Ireland
Politics in Northern Ireland differs to that in Great Britain. Rather than the battle being between left and right wing parties, the battle is between unionists and nationalists. Unionists want Northern Ireland to remain part of the United Kingdom and the nationalists are against Northern Ireland being part of the United Kingdom. The two largest unionist parties are the Ulster Unionist Party (UUP) and the Democratic Unionist Party (DUP). The two largest nationalist parties are Sinn Fein and the Social Democratic and Labour Party (SDLP). Often the unionists decide that the best chance of preventing a nationalist candidate from winning a seat is to field a single unionist.
For the 2015 general election, the UUP and the DUP have decided to enter an electoral pact by one of them standing aside in favour of the other in four seats.
For simplicity we will assume that all of the UUP and the DUP voters from the 2010 general election will go to the single unionist candidate.
) (DUP standing)
Belfast North is the only Belfast seat that returned a unionist at the last general election. It is held by the DUP with a 6% majority over Sinn Fein. Currently the combined unionist vote is larger than the combined nationalist vote so the pact should easily increase the DUP majority.
) (DUP standing)
Belfast East is the only seat in Northern Ireland held by the non-unionist and non-nationalist Alliance Party. The combined unionist vote last time exceeded 50% so it is likely that the DUP will take the seat. However, it is possible that the Alliance Party may hold on if it can persuade enough unionists to back it and if it can squeeze the small nationalist vote.
Fermanagh and South Tyrone
) (UUP standing)
Fermanagh and South Tyrone was last won by a unionist at the 1997 general election and was won by Sinn Fein at the 2001 general election. The UUP and the DUP fielded a single unionist candidate at the 2010 general election, but fell short of winning the seat by only 4 votes. It is hard to say which way this seat will go, although it is likely that Sinn Fein will benefit by squeezing the SDLP vote.
Newry and Armagh
) (UUP standing)
Newry and Armagh has not been in unionist hands since the 1980s. It was last won in 1983 due to a split in the nationalist vote. Since then it has been captured by the SDLP and was subsequently captured by Sinn Fein. A unionist winning this seat appears to be a long shot, but it is conceivable that a well balanced split in the nationalist vote could let the UUP through.
The UUP and the DUP were unable to agree a deal in Belfast South. Sinn Fein did not stand in Belfast South in the last general election, but they are this time so a split in the nationalist vote could have let a single unionist candidate through. There is a remote possibility that despite a split in the unionist vote, Belfast South could go to either the UUP or the DUP.
For the United Kingdom as a whole, most of this makes little difference to the final outcome of the 2015 general election. Probably the most likely outcome of this is no change at all. Let us suppose that the UUP win Fermanagh and South Tyrone from Sinn Fein. Sinn Fein are an abstentionist party meaning they do not vote in parliament. Therefore the implication of the UUP winning would be the opposition being up one seat which in a tight election could make all the difference, especially in a vote of no confidence.