Constituency profile: Lagan Valley illustrates explicitly the splits within the Ulster Unionists, as well as the campaigns for unionist and nationalist hearts.
Yet for all the rivalry within the UUP, the party still hopes to emerge on the other side of this election with an extra seat.
On the nationalist side, the SDLP is squaring up to a confident Sinn Féin effort to secure the one seat available to the nationalist community.
The area includes the new city of Lisburn and embraces the outer suburbs of West Belfast as well as a variety of small dormitory towns and villages. It is about 80 per cent Protestant and solidly unionist, although the SDLP proved in 1998 that a nationalist quota can be attained.
Leading unionist dissident, Mr Jeffrey Donaldson, is the area's MP having taken over from his close associate and former leader Lord Molyneaux.
Like Mr David Burnside in South Antrim, he has gained special permission to contest this Assembly election, despite being a member of another legislature.
The UUP is standing four candidates. Mr Donaldson is accompanied by Mr Billy Bell who has carved out something of a name for himself as the whistle-blowing chairman of the Assembly's public accounts committee. Ms Norah Beare and Mr Jim Kirkpatrick make up the ticket.
They face a DUP challenge from Assemblyman Mr Edwin Poots and Mr Andrew Hunter, the MP for Basingstoke and a former Conservative.
Mr Ivan Davis, another outgoing Assembly member, was not selected by the UUP and he is running as a pro-agreement Independent. What effect this will have on the Ulster Unionist total can only be guessed at.
The Progressive Unionists are also running a candidate and there is all to play for in that the UK Unionists, who picked up a seat last time, are not contesting the constituency on Wednesday.
Mr Séamus Close is defending his seat for the Alliance party - this constituency provided the party with its best result in the 2001 Westminster election - and he topped the poll in 1998.
The Conservatives are also fielding a candidate, as is the Workers Party.
The SDLP's Ms Patricia Lewsley had more than twice the Sinn Féin vote in 1998. But Mr Paul Butler is aiming to inflict a reversal this time for Sinn Féin.
In 2001 the SDLP stayed ahead of Sinn Féin, but with a smaller majority, in the Westminster poll. However, in the local government election on the same day, the party fell behind Sinn Féin.
Both parties insist they will take a seat.