Since his grip on his party in the House of Commons is scarcely tighter than John Major's on the Conservatives, it looks a little reckless. But given Trimble's pivotal role in the British Parliament over the next few months, it poses an immediate question: is this the beginning of a realignment on the British right, or just a cynical and mercenary quick fix? Or both?
It's quite a big moment: it appears to sever the increasingly frayed cord which has linked Conservatism and Unionism since the last century. It's impossible to imagine Trimble's predecessor, the old-school Sir James Molyneaux, playing fast and loose with the Tories like this.
Two big changes have been visible in the Tory party itself since 1979. One is obvious: that under John Major the Government has moved from prescriptive Unionism to one of theoretical neutrality over the Union. Underpinned by the principle that the future of the province should be whatever its people wanted it to be, it was this neutrality that was expressed by successive Northern Ireland secretaries, who said that London had no selfish strategic or economic interest in holding on to Northern Ireland. And this shift went largely unchallenged in the Tory party, because of the second, less obvious, change: that the intellectual leadership of Unionism within the party had begun to dissolve, at least in the House of Commons.
There is no longer an Airey Neave, or an Enoch Powell, or a John Biggs Davidson or an Ian Gow to provide that leadership. By demonstrating, albeit provocatively, that the Ulster Unionists are no longer blood brothers of the Conservatives, Trimble can argue that he is doing little more than holding a mirror to the Tories.
That isn't to deny the strong whiff of short-term expediency about the Goldsmith deal for both parties. Sir James and his allies have been hunting for months for the single MEP who would take their numbers in the European Parliament from 17 to 18, thus qualifying it as a formal grouping and making it eligible for funds and to serve on key committees. The transfer gives Nicholson and Goldsmith more influence in the European Parliament. And by agreeing to pursue Sir James's Euro-referendum proposal in their general-election campaign, the Unionists benefit directly up to polling day. Two hundred thousand pounds is quite a lot of money in Northern Ireland politics. The move was strongly opposed by both Ken Maginnis, a UUP vice- president and the party's security spokesman, who is on the more liberal wing of the party, and by John Taylor, Trimble's deputy. It's true that Mr Taylor's outrage is somewhat undermined by the fact that as Mr Nicholson's predecessor in the 1980s, he himself transferred from the mainstream European Democratic Group to the extreme-right grouping led by Jean-Marie Le Pen. And their claim that the move could cost them possible general election gains in East Belfast and North Down is doubtful. The critics nevertheless have a powerful argument: that just at the moment when the party is trying to prove its modernity, it has linked up with one of the more eccentric groups in European politics. Some close to Trimble insist that his Euro- scepticism (he will be a sponsor of Teresa Gorman's new-year bill calling for a referendum) is a vote-winner because of protestant suspicion of the EU in Northern Ireland. More impartial observers doubt this. For a start, the Unionist orthodoxy that Northern Ireland voted against joining the EEC in 1975 is really a myth: it's true that fewer voted to join in Northern Ireland than elsewhere in the UK, but there was still a 52 per cent majority in favour, and there are signs that hostility to the EU has if anything mellowed. So it still looks as though cash is the main tangible benefit.
But something else has annoyed Trimble's critics even more. There is a strong suspicion that David Burnside, lobbyist and close ally of Trimble, played a key role in sealing the match. Burnside refused to comment yesterday, but he has excellent contacts among the circle of right-wing Tories and former Tories who sympathise with Sir James. The only prominent member of this group actually to join Goldsmith is Lord McAlpine. But there are plenty of Thatcherite Tories - including some of those MPs in seats where Sir James has said he will not field candidates - who agree with his vision of a "renegotiated" relationship with Europe. And this may help to explain the symbolism of the move Trimble has made. For the UUP leader is almost certainly considering life after as well as before the election.
Trimble is probably genuine in saying that the move will not give Sir James direct leverage at Westminster over the next few months. The ferocity of the reaction among his own MPs suggests that Sir James wouldn't be able to call their tune anyway. Unionist supporters of the deal maintain that they have paid a low price for instilling a little fear into the Government. Trimble's own hopes of the election outcome are no doubt complex, but the best prospect for him is probably a Labour government with a narrow majority which has to take the Unionists into account; and a Tory opposition which quickly transforms itself back into a full-bloodedly Unionist party under a new, right-of-centre leadership. Under those circumstances the rupture with Conservatism might be reversible. Trimble may have damaged his own standing with those Unionist MPs who rightly believe that to deal with Sir James it helps to have a long spoon. His judgement has been doubtful. But by flirting with Goldsmith, Trimble has sent out a clear message about the kind of Tory party he hopes for when the election is over.