Then there are the men of Ulster. Normally, they have little power. But these laconic, beetle-browed fellows tend to regard close votes rather as remote coastal dwellers regard fatal shipwrecks, a happy and legitimate chance for plunder. Their demands are, no doubt, being discussed even now: item, one Northern Ireland select committee; item, one motorway kit, complete with Little Chef, superloos and flyovers; item, one ministerial speech designed to arouse maximum fury in Dublin . . . .
So, though the numbers look bad for Mr Major, there is a case for being cool-headed and sceptical about this looming defeat. A case, but not a particularly interesting one. So let us, having noted it, now wallow in overheated and irresponsible speculation of the kind everyone who is not currently resident in Downing Street much prefers. What if he loses?
There are no grounds for expecting an early general election. Two cabinet ministers have raised the thought, Peter Brooke in the context of the Christchurch by-election and Sir Patrick Mayhew in an attempt to scare the Ulster Unionist MPs. But Mr Major would have a thin case if, following a defeat on the social chapter, he asked the Queen for a dissolution. It is only a year since the general election, and the Conservatives still have a paper majority of 18.
With the party so low in the polls, Tory backbenchers regard the prospect with horror. Indeed, a representative group of them is meeting the Queen's private secretary for lunch on Thursday and will, if asked, tell him that Conservative MPs would not back the Prime Minister if he tried to go to the country. If it came to that, they would rather ditch him and soldier on with another leader.
Indeed, Mr Major himself, unless he has lost the will to carry on (and there's no sign of that), would be wise to play for time and hope that the continuing economic recovery improves his standing, as well as that of his party. Cabinet colleagues tell him that he should play any defeat long, promising to talk to Britain's EC partners and come back with further proposals in the autumn.
Delay, like a general election, or indeed a new leader, would not resolve the Maastricht dilemma. But Mr Major is likely to conclude that delay is better than sudden political death. A growing number of his MPs would like him gone, but there is no a keen challenger: nor has the ditch-Major campaign gathered much momentum. He has said privately that his toughest job was to hang on until the summer recess and he believes things can only improve thereafter. Much as Mr Major may dislike being aided by his good friend Lord Rees-Mogg, the journalist's legal challenge to Maastricht helps the Prime Minister because it postpones ratification and gives him an alibi for delay.
All the quick responses to a defeat are fraught with difficulties. Mr Major has used words about the importance of Maastricht which are so strong that he could not carry on if he ditched the treaty. Could he accept the social chapter? In a commonsense world, he could: it is vastly less important than the words of either side suggest. But political posturing has elevated it into a symbol of machismo. The opt-out deal was made necessary originally because of fears that Michael Howard, then Employment Secretary, would resign. Though he never threatened the Prime Minister with those words, his stand prevented any possibility of Mr Major agreeing to opt into a weaker social agreement.
The resulting opt-out was, however, hailed by Mr Major as a key success at Maastricht: for him to surrender it now would undermine him as fatally as ditching the treaty. It would produce cabinet resignations and a leadership challenge in the autumn.
The third immediate option is little better. The idea of simply ignoring a parliamentary defeat on the social chapter and going ahead with the ratification of Maastricht has been advocated by cabinet ministers. This has been seriously discussed in Downing Street and has caused sharp arguments inside Government. It may, even now, be Mr Major's favoured option. But a group of senior Tories, spreading well beyond the hardcore anti-Maastricht campaigners, would be outraged and would make their outrage public.
Resignations, including two from the cabinet, could well follow. These are the sort of circumstances in which cries of 'constitutional foul' could lead to a serious Major-must-go campaign. He might even lose a vote of confidence.
So there are no easy answers for this administration, struggling with an out-of-control party and a cantankerous legislature. I can find no senior minister who sounds confident about this week's confrontation. Each day seems to bring another Tory MP who says that Mr Major cannot survive. If he makes it through to the recess, the long lull of summer may allow him to rebuild his leadership. But he is weak, and struggling. His self-appointed mission of binding the Tory party's European wound has failed.