Leading article: What are you afraid of, Dave?

We come to the Michael Ashcroft question with the wide-eyed innocence of a 20-year-old voter. What was David Cameron thinking? The Independent on Sunday has been more favourably disposed towards him than towards any previous Conservative leader since we were founded two decades ago. He is more convincingly green, more liberal and more concerned with social justice than his predecessors. He seems refreshingly pragmatic, with an engaging manner and an apparent openness. Thus he brought many voters to first base. This newspaper was ready to consider the Conservative Party's election pitch with an open mind.

The detoxification seemed to have worked. But it was only the start. The next phase was to set out the positive appeal.

Instead, Mr Cameron has embarked on retoxification. We have been reminded that the Tory party is funded and run by rich people who seem to regard the payment of taxes as optional, and whose "patriotic duty" is to find a status that allows them to live in this country when they feel like it. As for openness, it has taken 10 years for Lord Ashcroft, the Tory party deputy chairman, to make a public statement about his tax affairs.

When Mr Cameron became leader, he was well aware of the delicacy of the party's relationship with the billionaire. Within two years Mr Brown was on the verge of calling an election, and the party needed money. What is puzzling is what happened after Mr Brown decided that he needed time to set out his vision. Mr Cameron is understood to have told colleagues that the party had to stop being "dependent" on Lord Ashcroft. Indeed, once the Tories were ahead again in the opinion polls, other donors became willing to dilute that dependency. Yet Mr Cameron failed to take this opportunity to clarify Lord Ashcroft's status.

Lord Ashcroft is not simply a donor. No doubt the Electoral Commission was satisfied that the donations from his company, Bearwood Corporate Services, were permissible (although how it could do so is not clear when it admitted it had been unable to obtain "meaningful information" about the ultimate source of the donations). But he was also elevated to the peerage on the recommendation of Mr Cameron's predecessor and shadow cabinet colleague, William Hague, and given a role in the party, in charge of the targeting operation in marginal seats.

In any circumstances, there was a legitimate public interest in knowing whether he had fulfilled the undertakings he gave as a condition of membership of the House of Lords. That interest was the more compelling because of his role in the Tory party, and yet he resisted it for all that time. He was forced to make a statement last week only because a Freedom of Information request, from a Labour MP in a marginal seat threatened by his campaign, was about to secure publication of his tax status.

What, then, was the Tory leader thinking? Did he imagine that Lord Ashcroft's obfuscation had gone on so long that they could make it to the election without further disclosure? Was he too trusting of a too-trusting Mr Hague? Did he think that it did not matter, or that Lord Ashcroft was too terrifying to sack? Or that it was all jolly awkward and, my goodness, is it time for my next meeting? None of the answers to these questions reflects well on Mr Cameron's judgement. We are told that Mr Cameron had several conversations with Lord Ashcroft about his tax status but "got little by way of response". This is feeble. How difficult can it be to say, even to a difficult and "very private" person: "I am entitled to know and the public is entitled to know, and if you don't accept that then it has been a pleasure working with you"?

The fact that several Labour donors are also non-doms is irrelevant. So they are, but they have always been open about their status. And the Conservative leader makes matters worse by presenting himself as a champion of openness. Two years ago, he set the standard: "Any arrangements we enter into are ones we are prepared to protect and defend in a court of public opinion." Since then, he has fallen short. And he knows it: hence he has turned on the media, accusing them of "flogging a dead horse".

Mr Cameron has, quite unnecessarily, moved his base camp and pitched it several miles farther down the mountain in preparation for his assault on the summit. It makes no sense, and undermines our confidence that he possesses the judgement required to be a successful prime minister.