AS make or break week in the Northern elections begins, signs of deep unease - and, in some cases, incipient panic - among the contending parties reflect the growing realisation that fortunes in this novel voting system may turn upon a mere whisker in terms of votes.
With only three days to polling day, the UUP will this morning launch a desperate last minute attempt to stave off the very real possibility that its dominance in the last Westminster and local elections could be devastatingly shattered by a multiple splintering of the pro union vote.
Mr David Trimble, whose judgment and leadership role could be seriously undermined if his party is pushed into third place behind the SDLP and DUP in terms of candidates elected, will put forward proposals on how the vagaries of the "list system" can be "managed" to maximise the UUP's performance.
The first and primary danger for the UUP, however, lies not in the untried voting system, but in the political uncertainties, fears and suspicions looming in the background of the election.
This volatile climate is the very sort of atmosphere which in the past has prompted large swathes of the middle ground, middle class unionist community to cast aside their natural distaste for intolerant and extreme positions and plump for the more fundamentalist, hard line parties, headed by the DUP.
No impartial opinion polls have been available so far to provide a guide to possible swings of allegiance among the electorate at large. Reports are circulating, however, of unofficial polls which are said to show a strong surge of support for the DUP.
If that is indeed the general trend, the UUP could be facing a strong psychological setback. The DUP leader, the Rev Ian Paisley, has demonstrated before that his powerful clarion call of "Not an inch" can appeal decisively to the Protestant masses in certain circumstances.
In the 1994 European election he easily reversed the UUP's normal dominance of the middle ground. The top three party rankings in that election, in terms of first preference votes, were: DUP 29.2 per cent, SDLP 28.9 per cent and UUP 23.8 per cent.
This contrasted sharply with the results of the 1992 Westminster election: UUP 34.5 per cent, SDLP 23.5 per cent and DUP 13.1 percent.
In the 1993 district council elections the UUP had also demonstrated its broad claim to reflect mainstream unionist opinion. The outcome there was: UUP 29.4 per cent, SDLP 22.0 per cent and DUP 17.3 per cent.
The DUP success in the European election, compared with its relegation to third place in the other contests, could be said to reflect the powerful personal electoral pull of Dr Paisley and the voters distrust or dislike of lesser DUP personalities.
But it showed most convincingly that there is a potential floating vote of between 10 and 15 per cent of the pro union electorate, for whom personality can outweigh policies if it comes to a head to head contest.
The unnerving factor for the UUP in Thursday's poll is that the ballot paper will carry the names of 11 parties which can each be said to be carrying a pro union banner.
The fear is that this could have a "shredding" effect on the unionist vote and in the final analysis reduce the pro union representation in the forum and the all party talks; particularly because there is no transferring of votes to ensure proportional representation.
The Green Party candidate, Mr Peter Emerson, an indefatigable student of electoral systems, has provided an example, a set of hypothetical results which demonstrates clearly that a mere handful of votes either way can make all the difference to the allocation of the fifth and last seat in the five seater constituencies.
The contenders for this vital final seat in each of the 18 constituencies will almost certainly be the four parties at the top of the poll.
Unlike the PR-STV system, minority parties and independents who come further down the list will not have the possibility of being hoisted by transfers to a position of seriously contending for the last seat. They will have to place their hopes in the "topping up" process, which will be based on aggregate votes throughout all 8 constituencies.
The possible distortions are demonstrated in Mr Emerson's hypothetical example. It shows how a party which tops the poll with 37 per cent of the votes may take three of the five seats (60 per cent) in a constituency, or just two (40 per cent), depending on a difference of just three votes in that party's overall support.
The real fascination concerns the order in which the UUP SDLP and DUP will come in terms of overall numbers of seats gained. The growing impression is that the SDLP may even come first in this contest if and it is a big if it can bring out its traditional vote in full strength.
Mr Robert McCartney's UK Unionist Party and the two fringe loyalist parties will eat into the support for both the UUP and the DUP, increasing the SDLP's chances of emerging top of the big three parties. But this prospect could be scotched if there is a massive popular swing to the DUP.
Sinn Fein traditionally comes fourth in terms of votes and will therefore be in contention for the fifth and last seat in many constituencies. But how this turns out in terms of actual seats gained will hinge on very marginal differences in the votes gained by the big parties ahead of it.
The Alliance Party should be in with a chance of a very good performance in this election, but is up against several imponderables. The Northern Ireland Women's Coalition, the Greens and the "Peace People" party, Democratic Partnership, all seem likely to chip away chunks of Alliance's natural, non sectarian support base.
The glittering prize in this election, of course, is not really concerned with the number of seats gained (or, more correctly, delegates elected). The crucial challenge for the smaller parties is, firstly, to get any candidates elected at all, and thus gain the right to representation at the all party talks.
Failing any success in the constituency elections, the smaller parties will have their own separate electoral coniest on the regional list. Their aggregate votes in all the constituencies they contest will be used to place them in descending order, and the first 10 on this ranking ladder will be entitled to have two candidates from their regional lists returned as delegates.
The Independent candidate, Mr Man Chambers, has pointed out that the ninth and 10th places on the regional list will decide whether there is a nationalist or pro union majority around the negotiating table.
The question of a "majority" at the talks table, however, is not the most vital element, since the negotiations are intended to be conducted on a "consensus" basis. But, for all the groups who are not among the five big parties, the prestige and the bonus resides in getting to the table at all.
Interest in Thursday's poll still appears to be low key, but seasoned observers perceive that there is a dormant sense of the historic nature of the occasion underlying the apparent outward apathy. The Northern Ireland electorate, sometimes capricious and always volatile, could yet surprise everybody.