The odd couple

David McKittrick on how some people will vote for both Adams and Trimble

THE intriguing prospect of people casting votes for both Sinn Fein and the Ulster Unionist party has been raised by the voting system for next month's elections to the new Belfast assembly.

Large numbers may not make the political leap involved in backing both Gerry Adams and David Trimble, but it is a fair bet that quite a few will do so for purely tactical reasons.

Under the proportional representation system, voters can - and do - give support to a multiplicity of candidates, unlike the Westminster first- past-the-post system, in which people simply cast a single vote.

With PR in use in Northern Ireland since the early 1970s, people are accustomed to voting first for the candidate of their choice and then transferring to others. Judicious use of the system can help not only to elect their candidates of choice, but also to harm the chances of those they most dislike.

With a political landscape significantly altered by the referendum which endorsed the Good Friday agreement, some observers estimate that pro-agreement parties could greatly benefit from new transfer patterns. One veteran politician said: "The new assembly will have 108 members. I reckon transfer votes could be worth a dozen seats for the pro-agreement side."

The intricacies of PR could thus have a significant effect on the outcome of the election. Under PR, voters are given a list of individuals. They place a 1 beside their first choice, a 2 at their second choice and so on, voting as many times as they wish.

At the subsequent count those candidates who acquire enough votes to meet a certain formula are declared elected. Extra votes, known as their surplus, are then distributed among the remaining candidates.

Up to now, voters for David Trimble's Unionist party and the Rev Ian Paisley's Democratic Unionists have freely traded transfers. Two-thirds of UUP voters have voted for their party's candidates and given lower preference votes to the DUP.

This time, the established pattern will be disrupted as Mr Trimble's party is advising supporters to transfer not to Mr Paisley but to other pro-agreement parties, except Sinn Fein.

In most constituencies this in effect means UUP voters are being asked to transfer to John Hume's nationalist SDLP. If this advice is followed Mr Paisley will undoubtedly suffer, since UUP transfers have always gained him extra seats.

On the nationalist side the change is set to be even more strikingly beneficial to the pro-agreement cause. Since nationalists are almost universally in favour, many can be expected to spread their votes over pro-agreement parties.

This will lead some of them to vote for the parties of both Mr Adams and Mr Trimble, since both are, in very different ways, in favour of the accord. Thus it is that many centrist nationalists will end up voting tactically for the two men in the knowledge that doing so will help keep Mr Paisley out.