The American feminist author Andrea Dworkin has died at her home in Washington, aged 58. Dworkin, originally from Camden, New Jersey, had been ill for several years. She suffered from a number of ailments, including osteoarthritis.

Dworkin sparked international debate by arguing that pornography was a violation of women's rights and a precursor to rape. Her book, Woman Hating, published when she was 27, was the first of more than a dozen books on the subject.

Dworkin also helped draft a law in the city of Minneapolis that recognised pornography as sexual discrimination.

Much has been written this week about the influence of the radical feminist - apart from the truth: that she set the women's movement back 20 years, says Havana Marking

When Jenni Murray asked yesterday what Dworkin had actually achieved in her life. It was acknowledged that while pornography was on the increase, at least we could discuss it now. But what no one said, and what no one wrote in Dworkin's obituaries, was this: Dworkin's true legacy has been that far too many young women today would rather be bitten by a rabid dog than be considered a feminist.

Since the 1970s, said this paper's obituary, Dworkin symbolised women's war against sexual violence. Rape, paedophilia and domestic abuse needed, and obviously still need, to be hounded out of our society. How brilliant that there was someone willing to stand up and talk about it - to say to the world: "his has happened to me, and it happens to a lot of women and it has got to stop. But Dworkin's radical writing and hugely controversial - practically melodramatic - ideas not only pushed the argument as far as it could go, but pushed it off the cliff of credibility.

Dworkin achieved fame for her stance against pornography. As the film editor of Scarlet magazine (Britain's sex mag for women) and a self-proclaimed lover of porn, one could imagine that I was dead against everything she had to say on this matter. But that's not true. Elements of her arguments are tenable, and I agree that the makers of porn should have a legal incentive to create pornography that does not abuse. People should not be able to incite violence towards women, in the same way that people are not allowed to incite racial hatred.

But the problem with Dworkin's attitude to porn sums up everything that can now be held against her. Her definition of porn and what is considered harmful is hugely misleading. In Pornography: Men Possessing Women, Dworkin used the word pornography knowing that it was different from society's understanding of the term. It was not just sex between adults recorded to inspire erotic and sexually arousing feelings; it was any sex act that involved degradation of women in a sexual context. "Pornography is a celebration of rape and injury to women ... " and by her definition, it was.

The deliberate blurring of these definitions is Dworkin's fundamental error and led ultimately to her malignment and the ease with which (male-led) society was able to demonise her. But it got her good headlines at first and if you court such controversy you play a very dangerous game. Dangerous not only for yourself, but for the women you claim to represent.

Dworkin redefined sex workers as helpless, passive victims - whereas before they were viewed as fallen, evil women. But as Ana Lopes, founder of the British Sex Workers Union and a committed feminist, explains: That has not changed the conditions under which women perform sex work. It has done nothing to improve their lives. On the contrary, they [radical feminists] have been a huge barrier to sex workers' empowerment and self-organisation. Sex workers need the support of advocates and allies in order to gather enough resources to stand up for their rights successfully. The women's movement is one of the most obvious allies - but if feminists are busy protesting against prostitution and pornography as a concept, it is clear that sex workers cannot count on their help.