Leading article: Cameron is entitled to a past

That Mr Bush should have prospered in a democracy more censorious about drugs than our own should encourage David Cameron, the frontrunner for the Conservative leadership. It remains a great pity, however, that our society is so immature that Mr Cameron feels - probably rightly - that it would destroy his chances to be specific about his experience of illegal drugs. He should be in a position to give a straight answer about past drug use without fearing that he would be hounded out of the race.

Someone who aspires to lead the country should respect the law, but the statute of limitations applies in politics as much as it applies to most other parts of life. Although generally Mr Cameron has carried himself well, he has not phrased this point felicitously. He says that he should not be held to account for "mistakes" he made before he knew he was going to be a politician. The trouble is that this implies that he started to obey the law only because he wanted to be an MP. What matters about his past mistakes is that he should have learnt from them. As we now know, he knows the harm that drugs can do from the "dreadful problem" of "someone very close in my family". It also ought to be possible for him to be open about his own drug use and how he has learnt from it.

The three people who would be best advised to stay out of this struggle are Mr Cameron's rivals. David Davis proved that he has learnt nothing about the Tories' reputation as the nasty party by saying that no one who had taken class-A drugs should be prime minister - "if it was recent". As we report today, this is the same Mr Davis who, as party chairman, told Conservative MPs not to answer questions about drug use. He is right, though, that "recent" drug use should rule Mr Cameron out of contention.

Assuming that he has not taken illegal drugs since, to use his phrase, he "entered politics", at the Conservative Research Department in 1988, Mr Cameron should be judged on his policies. There should be no dispute about the damage that drugs can do and no one should condone the use of class-A drugs such as cocaine or ecstasy. The debate should be about how best to minimise the harm that drugs do to people, and on this Mr Cameron's contribution has been thoughtful and impressive. He showed no little courage in departing from his party's traditional line on the Home Affairs select committee. He advocates a constructive policy of intensive rehabilitation for addicts as an alternative to prison. Almost alone in his party he recognises that when it comes to one of the most important causes of crime, prison does not work. That is the debate about drugs in which the Conservative Party and the press should be engaged. Instead, Mr Cameron finds himself embroiled in a mean-spirited, backward-looking witch hunt that reflects poorly on the level of public debate in this country.

It would have been better had Mr Cameron been able to be more candid. But he has to work with the Tory party and the media that we have got, and his defence of his right to remain silent about aspects of his past is perfectly justified. Not least because British political life would be even more denuded of talent than it already is if anyone who had used an illegal drug were barred from the top job.

It is an important test of the Tory party's ability to keep pace with social change that it should hold firm in the face of an assault by the traditionalist press. It must judge Mr Cameron on how he might lead the party in the future, rather than on what he did in private a long time ago.