Bruce Anderson: Mr Duncan Smith is no extremist, but he is a winner

Many tory MPs are now feeling as if they have spent the past 11 weeks at the dentist's, with no anaesthetic – yet there are still 16 days to go before the leadership result is declared. Almost everyone agrees that the election procedure will have to be altered, though it is not easy to see how this could be done while retaining one member one vote. Perhaps computerisation could provide the answer. But the current arrangements have maximised exhaustion, ill-temper and damage to the party's standing.

Despite the further interval before the declaration, the contest would appear to be over. According to the published polls, Iain Duncan Smith will win a sizeable majority; the two rival camps' private polling is thought to confirm that verdict.

If this proves to be the case, Mr Duncan Smith should feel entitled to take about an hour off to thank his supporters and receive their congratulations. Then he will have to embark on an even greater challenge than winning the leadership. He will have to ensure that it is a worthwhile victory.

The first few weeks will be crucial, as William Hague's experience proved. Despite his supporters' high hopes and his own considerable qualities, Mr Hague somehow forfeited public esteem within about three months of becoming leader. He was never able to recover from this and persuade enough voters that he was prime-minister material.

Mr Duncan Smith faces a similar task. By about Christmas time, the public will have formed a judgement about him. Once this has happened, it will be hard to persuade them to change their minds.

Formidable forces are ready to assist them to form an adverse judgement. Downing Street has now had several weeks to organise its pre-emptive strike against Mr Duncan Smith. The voters will be assured that he is an extremist; that under him, the Tory Party will be virtually indistinguishable from the National Front; and that he is unelectable.

In this campaign, Downing Street will have allies, and not only the BBC. Kenneth Clarke will have to remain silent, lest he seem a bad loser – and besides, there must still be some third world countries which he has not yet visited and where they are not yet smoking enough cigarettes. But neither Michael Heseltine nor Steven Norris will worry about being bad losers, and they are bound to be reinforced by a swarm of minor figures eager for a quarter of an hour of fame. Among them, no doubt, will be Tristan Garel Jones – now Lord Garel Jones – a former junior minister who has become the Lucrezia Borgia of the Clarke campaign, spreading poison wherever he can. "Have you got Ids?'' is one of his favourite comments.

In the last Parliament, several of the leading Tory Europhiles would have been happy to disrupt the Tory party in order to assist Tony Blair to join the euro. They are still willing to perform that service, and will not lightly forgive Mr Duncan Smith for thwarting the Europhiles' final bid to take over the Tory party. They and their allies in the press will do everything possible to destroy Mr Duncan Smith. He is tough, but he will need to be braced for an onslaught.

In resisting it, he will have one asset. The truth may be an undervalued commodity in contemporary politics, but it can retain its potency if skilfully deployed. There is no reason why Mr Duncan Smith's enemies' distortions should prevail. After all, he has a pleasant personality, and seems to be more photogenic than Mr Hague, while also possessing a more acceptable voice. So he merely needs to find the right language to reassure the voters and to rebut the charge of extremism.

Iain Duncan Smith does have strong views. He believes in the pound, the family, the monarchy and the British constitution. He believes in law and order, strict control of inflation, strong defences and in Ulster's right to remain British. There are many on the left who would regard such views as extremist, in order to render them illegitimate and to exclude them from political debate. But it would be negligent of the Tories to allow such lefties to succeed, because if Mr Duncan Smith is an extremist for holding those views, it is a label that he shares with a substantial majority of the electorate.

Nor is there any reason for him to take his political stand solely around traditional Tory values. He also believes that governments have a duty to help the needy, and that the British people are entitled to substantial improvements in the quality of education and the level of health care. Throughout his campaign, he has insisted on the need for a radical policy review, to enable the Tory party to challenge Labour's electoral grip on the public services. If the next election is to be decided on the battleground of new thinking, there is no foreordained reason why Mr Duncan Smith's Tories should lose.

He also has some useful adjutants, such as Michael Ancram, Stephen O'Brien, Eleanor Laing, Bernard Jenkin, Liam Fox, David MacLean and David Davis. With the possible exception of Mr Duncan Smith himself, no Tory politician has increased his stature during the past two months to the same extent as Mr Davis has. He must be a strong candidate for the shadow chancellorship on a Duncan Smith frontbench.

But Mr Duncan Smith is fully aware of the need to recruit talent from across the party. Damian Green was one of the few effective members of the Portillo high command before moving to the Clarke camp; he would be a good choice for the party chairmanship. Mr Duncan Smith will also wish to recruit Archie Norman, David Willetts and Tim Yeo from the Portillista ranks, and there ought to be a role for Nicholas Soames; shadow minister of food, perhaps?

Since Mr Portillo's defeat, Francis Maude has signalled his unhappiness and has insisted that the Tory party is imperilled by the lack of fresh thinking. It might be a good idea for Mr Duncan Smith to take him at his word. Twenty-five years ago, Francis Maude's father, Angus, did an outstanding job as Margaret Thatcher's Chairman of the Conservative research department. It may be time to make that post hereditary.

The Tory front bench may be short of heavyweights, but there are plenty of attractive youngsters who are fully paid-up members of the human race and who could assist Mr Duncan Smith to deal with the charge of extremism.

The next few weeks will be critical, but the signs are not discouraging. Over the past two months, Mr Duncan Smith has proved that he has the capacity to surprise his own supporters by rising almost effortlessly to new levels of challenge. There is no reason to believe that this process is at an end. He is 48 years old, untested and unknown. When they were 48 years old, that was also true of Clement Atlee, Harold Macmillan and Margaret Thatcher.

It is too early to be certain whether Mr Duncan Smith has that much potential, but over the past couple of months, he has visibly grown into the job of leadership. Over the next couple of months, we will see whether he has grown enough.