The Maastricht Debate: The haunting resonance of a beaten leader's last show: John Major's tactics will weaken his already fragile hold over party colleagues, writes Andrew Marr

TODAY John Major binds his own future as Prime Minister to the policy that lies at the heart of his Government's meaning. He has detonated what one of his close friends called 'the nuclear option': back the social chapter opt-out or I'll blow the party apart at a general election. Given the question, it seems certain he will win.

But given the question, a win means less. It can hardly be used to bolster Mr Major's fragile leadership. If you threaten your party colleagues with self-immolation at a general election and they decline to destroy themselves, you can hardly claim that they have thereby demonstrated their undying support for you. A confidence motion? It sounds more like a motion against mass suicide.

Nor does the story stop there. The Tory party may not be ready to throw itself on the mercy of a resentful electorate but it has, again, displayed its grievous wounds. Mr Major came to power determined, above all, to be the leader who reunited this party of government. Instead, the Opposition has won its first significant Commons victory since the 1970s. And the party of government looks like a rudderless hulk, taking water and drifting.

Such weakness will darken the rest of Mr Major's year. It will give a deeper resonance to the looming Christchurch by-election defeat. Throughout local associations, resentment against the rebels will mingle with depression about Mr Major. This may prove a combustible cocktail when the Conservatives meet at October's conference. Assuming Mr Major hangs on, a challenge to his leadership in November is a serious possibility. If he survived that, attention would then turn to European and local elections next spring. They could finish him.

Faced with that dark valley, has the Prime Minister got the courage to carry on? For someone so often derided as a ditherer, he is a curiously stubborn man. Economists predict two or three years of strong growth and low inflation before Britain's trade deficit starts to seem critical. Strange though it may seem today, there are good reasons for predicting a Tory election victory in 1995-6. Mr Major would like to stay around to enjoy it. A more resonant question is whether the party will let him.

Oh come on, Mr Major would say. This is hype: I was beaten by 'a cynical and unscrupulous vote'.

It will not wash. He played by the rules of the parliamentary game and last night, he lost. The rules say nothing, thank God, about the motives of members when they vote. The very fact that ministers were ready to bargain with Ulster Unionists exposes the hollowness of the Prime Minister's outrage at the coalition ranged against him. The Unionists are against Maastricht. Was it not, therefore, just as 'cynical and unscrupulous' for the Government to try to buy their votes?

This was a dirty battle on both sides: no one involved had the right to moralise about it.

So Mr Major was right to draw back from his dangerous threat to set that vote aside. If decisions of the Commons can be retrospectively unpicked because of strange alliances in the voting lobbies, how many past votes could we now declare illegitimate?

Mr Major is badly wounded. He fought hard through yesterday's parliamentary confrontation. But to some, his comment that he was finding the debate 'more fun' than he expected had a haunting resonance. Margaret Thatcher once said: 'I'm enjoying this]' When? On 22 November 1990, during her last Commons performance as Prime Minister.