WHAT will David Trimble do? John Major and Tony Blair will doubtless ask themselves that question on numerous occasions in the coming weeks. The death last night of Conservative MP lain Mills has taken Mr Major's government into a minority, with the Wirral by election still to come. The nine Ulster Unionist MPs now hold the whip hand.
This is heady stuff for a minority party. The stuff of their dreams, perhaps. But more than a bit intimidating too. To prop up a dying administration and risk alienating the perceived successor? Or force an early contest which results in a large Labour majority and the loss of precious influence?
These were the questions which exercised the nine last week when they met to review the prospects for the final weeks of this parliament. They remain unresolved. To compound the uncertainty for Mr Major and Mr Blair, it is openly acknowledged that Mr Trimble presides over a divided parliamentary party.
Mr Trimble's own disposition is unclear, although those close to him have argued he should buy influence with Labour now. However, a majority of his MPs are clearly prepared to overrule their leader.
It has emerged that is precisely what happened over the fisheries vote in the Commons before the Christmas recess. With less than an hour to the division, Mr Trimble told his colleagues he proposed to vote against the government. The majority refused - obliging Mr Trimble, and his deputy, John Taylor, to abstain.
The party leadership has attempted to make light of the split - attributing the "misunderstanding" to conflicting advice from the leaders of Northern Ireland's trawlermen. But other sources readily confirmed that a serious question mark had been raised over the leadership's ability to deliver the unionist bloc.
Mr Trimble appears quite philosophical about this state of affairs. His problem derives largely from the fact that he beat four of his colleagues in the 1995 contest to succeed Sir James Molyneaux. The old guard has never quite been reconciled to Mr Trimble's leadership, or overly respectful of his overwhelming mandate from the constituency based Ulster Unionist Council.
PERSONAL rivalries apart, there is an underlying anxiety to play the parliamentary card right. Mr Trimble says he will not act "capriciously" and will judge each Commons vote on the merits of the issue. Some of his number quarrel with this - insisting the party could end up looking ridiculous if it were to inflict defeat on the government one day and vote in the contrary manner in a confidence vote the next.
Their preference is for the formula which precludes ending the life of the parliament "prematurely" - provided, of course, the government governs "in the best interests of the United Kingdom as a whole, and of Northern Ireland in particular". The contention is that this is a proper and responsible position for a small minority party to take - and one which it could sustain with an incoming administration as with the present one. Altogether less grandiose, and more real, is the attendant hope: that if Mr Major can play it long, Labour's lead will narrow and the incoming administration could find itself just as much in need of Ulster Unionist friends.
For the moment at least, then, Mr Major's friends seem set to sustain him. The Ulster Unionists have won concessions on fish quotas, and can see the beginning of the end of Northern Ireland's BSE crisis.
They were also delighted at Mr Major's rejection of the most recent proposals from John Hume and Gerry Adams, setting terms for the restoration of the IRA ceasefire.
It could of course, to coin a phrase, yet end in tears. With the collapse of the pairing system at Westminster, Mr Major's government remains more than ever at the mercy of events. The final days could acquire a momentum of their own. If the Wirral echoes Mr Blair's demand for a general election now, Mr Trimble might be tempted to appeal to his party over the heads of his reluctant MPs. It may not even come to that. In truth, they could abandon Mr Major just as ruthlessly as they did Jim Callaghan in 1979.
And it is, perhaps, to 1979 that the Ulster Unionists should be looking as they consider their strategy - not just for the next few weeks but for the longer term.
Mr Trimble and his colleagues might enjoy their place in the sun as Britain awaits its opportunity at the polls. But if the opinion polls are correct, something of a psychological shock awaits them in the next parliament.
Mr Trimble's predecessor in Upper Bann - the late Harold McCusker - suffered something of the kind 18 years ago. Having been the object of every Labour minister's attentions, he became disenchanted with Westminster as he adjusted to the very different existence of a minority party MP under a government with a solid working majority.
It is hardly, too early for the Ulster Unionist Party's strategists to be addressing such scenario. For just weeks after the general election, an even lurks around the corner which could provide the first serious test of a Blair government Drumcree Mark Three.
Tony Blair let it be known that he was personally deeply offended by the events surrounding last year's Orange march at Drumcree. The Labour leadership has no doubt that colossal injury was, inflicted on community relations, on the reputation of the RUC, on the very fabric, indeed, of direct rule. Even, senior Orangemen think it scarcely conceivable that Prime Minister Blair (or Prime Minister Major, come to that) would or could permit a repeat performance.
Mo Mowlam, the shadow Northern Secretary, knows the nature of modern unionism. She understands well enough that the UUP lurched significantly to the right in 1995; that David Trimble was elected leader by a party which believed his predecessor had beef "too accommodating" to the British government; and that his mandate was not to make fresh, "concessions" but to claw back round unionists saw as already lost. She understands too, as Mr Trimble's friends will tell you that the MP for Upper Bann has little choice, but to stand by his local Orangemen in any dispute over their historic "right" to march.
But if Blair and Mowlam recognise Trimble as the product of Drumcree, they are unlikely to accept that they, or he, should be the prisoners of it. They believe a new culture must surround the question of Ulster's traditional parades, if the culture of apartheid type boycott is not to poison the entire Northern Ireland system. And while short on ideas as to where the resolution lies, senior unionists agree that a third "siege" would be ruinous to their future relationship with a new British government.
SOME of Mr Trimble's unionist opponents have promoted the notion of Drumcree as an annual benchmark by which to judge his leadership - a recurring virility test, as it were. But prudent unionists surely will ponder that Mr Blair, if elected, might be seeking a virility test of his own. Nor is it credible that Mr Trimble, hailed by many as a moderniser, could settle for Drumcree as an annual litmus test for the strength or weakness of the Union.
In Dublin the idea almost beggars belief. Key players there have long insisted that the challenge facing unionism and the British government of the day is to reconcile Northern Ireland Catholics to the Union.
But they manifestly will not be reconciled to a Union seen as an instrument of sectarian ascendancy. The challenge will grow more difficult if, as seems probable, the Provisional IRA were to greet the election of a new government with a fresh "peace" overture. And for all Mr Trimble's aspiration to speak for "the greater number" in Northern Ireland, it will be mission impossible if unionists allow themselves to be cast as the party for confrontation. Sinn Fein will hardly be unhappy to see Northern Ireland once more teeter towards the edge of the abyss.
Mo Mowlam has angered David Trimble with her constant refrain that "the status quo is not an option". But if the constitutional status quo is to be maintained, it requires a new and balanced political dispensation. The need for a deal is implicit in the unionist parties acceptance of the three stranded talks under an independent, American chairmanship. The smart response to the general election, whatever its outcome, would surely be to end the procedural play and let the real negotiations begin.