Leading article: A moderniser must have the courage of his convictions

The Conservatives have started their annual conference in the most extraordinary circumstances. After being ahead in the polls for most of the first half of the year, they trail badly now. And within days the party could be fighting a general election campaign. Yet even without the possibility of an autumn election, Mr Cameron would still be facing a make-or-break party conference. No opposition party has been this far behind in the opinion polls and won the subsequent election. So Mr Cameron faces a defining week for his leadership – and quite possibly for the future of his party.

Over the past 10 years, Conservative leaders have faced immense pressure to move rightwards when lagging in the polls. In their different ways Messrs Hague, Duncan Smith and Howard were unable to resist the lure of populism. Recently, Mr Cameron, too, has shown signs of heading down the same cul-de-sac. He has talked recklessly about anarchy in the UK, having previously espoused a more optimistic outlook. Only a year ago, he was preaching the politics of optimism; now his focus has shifted from progressive causes, such as the environment and quality of life, towards the traditional Tory causes of tax cuts, crime, Europe and immigration.

Yet Mr Cameron has less excuse than his predecessors to heed the right-wing populists' call because his earlier strategic approach was reasonably successful. He enjoyed significant electoral success when he championed green issues and policies relating to the quality of life. Indeed, the very gusto with which he made his early pitch means that he will command even less credibility than he might otherwise have done if he takes a more overtly right-wing stance this week.

Not all the Conservatives' current difficulties can be laid at Mr Cameron's door. In retrospect, their early poll leads can largely be explained by the unpopularity of Tony Blair. The Conservative leadership made a possibly fatal miscalculation in assuming that Gordon Brown would be an easier political opponent. Even without that mistake, however, they would still have faced the challenge of dealing with such a sure-footed strategist. The Conservatives also seek power at a time when, in spite of the recent banking crisis, the economy continues to hold up reasonably well. In 1997, Labour benefited from the Conservative government's trauma after Britain's exit from the ERM. There has been no equivalent earthquake under Labour yet.

Still, Mr Cameron and his fractious party are not entirely at the mercy of events. Two factors have made the situation worse for them. One is that Mr Cameron seems to have been seduced by the siren voices of the right, despite the lessons of recent history. The other related factor is a lack of coherence and credibility arising from that shift. Mr Cameron can address both this week by reverting to his early agenda, both in tone and in the policies he chooses to highlight. He must also ensure that themes and policies interconnect in ways that are accessible.

In his BBC interview yesterday, Mr Cameron took viewers on a rather vague route, announcing that some proposals from his policy review were being dropped, others accepted and that, although there would be no "upfront tax cuts", there would still be plenty of tax cuts announced in the coming days. The message needs clearer definition.

Mr Cameron set the Blackpool stage alight two years ago during the leadership contest. He has to do so again this week. He needs to rediscover the modernising zeal and political courage that won him the leadership and propelled the Conservatives into an opinion poll lead that they can only dream about now.

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