Andrew Grice: Memo to IDS: you're in a hole, so stop digging

Politics is a weird trade and not an exact science, but Iain Duncan Smith has managed to break almost every rule in the book in the last week with his extraordinary "unite or die" gamble.

"When in a hole, stop digging," was a favourite maxim of both Denis Healey and Bernard Ingham. How the Conservatives could do with a lost leader like Healey to call up now, or someone with the experience and media savvy of Ingham, Margaret Thatcher's press secretary.

Any media story that runs for only one day doesn't normally spell trouble because ordinary folk – "the people in the Two Ferrets in Hebden Bridge," as Ingham called them – will barely notice it. By attacking the MPs who voted against his hard line on gay adoption, Duncan Smith poured a gallon of petrol on a small bonfire that would barely have flickered in the eyes of most real people (as opposed to those who, like me, live in the Westminster village).

There was no need to fuel the story by issuing his "personal statement", one of the most bizarre events I have witnessed in my 20 years in the village. It reminded me of the "vote of confidence" given to Michael Foot, the hapless Labour leader, in the middle of the 1983 general election campaign, the nadir of his party's fortunes.

Another good rule is to decide who your enemies are. Neil Kinnock chose Militant and expelled its leaders. Tony Blair picked a fight with Old Labour over Clause IV that he knew he would win. In contrast, Duncan Smith is making enemies on his own side; he knows he needs to be a moderniser but cannot hide his traditionalist instincts.

"Grow a thick skin" is another good maxim. William Hague's paranoia about "plotting" by Michael Portillo seems to have infected Duncan Smith too. He has enough problems on his plate and doesn't need to invent any more.

As Opposition leader, Tony Blair would often tell his aides: "Let's work out where we want to be and then decide how to get from A to B." Such a strategy should be common sense to a former soldier such as Duncan Smith. Yet he had no follow-through after making his desperate plea for unity; he could not discipline a quarter of his MPs.

All he did was to provoke them into hitting back to deny his allegation of sabotaging his leadership, thus breaking another golden rule: "divided parties lose elections." Why his so-called advisers did not advise him his plea would be spurned is completely beyond me.

Duncan Smith badly needs to bring some more experienced players into his team of friends and Shadow Cabinet allies, some of whom are lower division players struggling in the Premier League. He needs people who can tell him when it is better to do nothing than to thrash around.

In as much as Duncan Smith had a strategy, it was to persuade grassroots Tories to tell their MPs to rally behind him. True, one of the few cards up his sleeve is that he is the first Tory leader to be elected by the party's 350,000 members. But although the members had the power to choose him, it is the MPs who have the power to sack him under the "halfway house" system bequeathed by William Hague.

Only a third of Duncan Smith's MPs voted for him last year; more wanted Kenneth Clarke. Patrolling the Commons corridors this week, it was not difficult to find Tory MPs who backed Duncan Smith in last year's leadership election but now think that they made a terrible mistake. Unfortunately for the Tory leader, some of them are determined to correct their error. "He will be gone by Christmas," one promised me.

For many MPs, it is about saving their own skins. An opinion poll published yesterday suggested only seven out of 10 people who voted Tory last year would support the party now – a terrible indictment of Duncan Smith. As David Mellor argued yesterday, it is no longer barmy to suggest that the Liberal Democrats can overtake the Tories.

However, all is not yet lost for the Tory leader. Another cardinal rule of politics is to learn from your mistakes, and he has plenty to learn from. By the end of the week, some Tory MPs had calmed down a little as they realised the public might think even worse of a party that assassinated another leader.

There is no obvious alternative to Duncan Smith who could unite the party and win back the lost Tory voters. The MPs might go for Clarke, but I suspect the members, who have the final say, would again vote for anyone but him. So the party might be back to square one, with a leader who lacks authority over his MPs.

Duncan Smith does possess an inner steel that the public never sees. He is going to need it if he is to win the right to lead the party into the general election. In my view, he has got to come off the fence, cut his ties with his mentor Norman Tebbit, take on the Tory traditionalists and show us he is a moderniser in his heart as well as his head. There would be painful casualties, but the vast majority of the Tory army would march with him, and they just want to be led. He might yet surprise us.

Duncan Smith's allies complain that the Tories do not have a convenient dragon to slay like Clause IV. But they need to find a totemic example of change for the voters to get the message. Why not support the abolition of Section 28? Why not say that taxes need to rise to show they really are serious about saving public services?

a.grice@independent.co.uk