BOOK REVIEW / Queen moves to check porn advance: Natasha Walter questions the anti-pornography arguments of one of feminism's most vocal preachers: Only words - Catharine A MacKinnon: HarperCollins, pounds 9.99

CATHARINE MacKinnon is a powerful and successful woman. She is a professor of law at the University of Michigan; she was responsible for making some forms of sexual harassment legally actionable in the States; she has maintained a high profile on behalf of Bosnian rape victims; she is interviewed in publications from the Guardian to Vogue; her latest book, Only Words, received feature-length review coverage in almost every newspaper and journal in the Anglo-American world; she appears on television to argue its thesis.

But Catharine MacKinnon has this to say about women's relation to language and the law: 'You learn that language does not belong to you, that you cannot use it to say what you know . . . You learn that your reality subsists somewhere beneath the socially real - totally exposed but invisible, screaming yet inaudible . . .'

MacKinnon thus arrogates to herself and to all other women the status of perpetual victims. By sliding parallels, she even makes the position of women in Britain and the United States today analogous to that of black American slaves or Jews in the Third Reich: 'What the Jews in Germany were told by the Nazis (and the rest of the world) in the 1930s (was) Accept the freedom of your abusers. This best protects you in the end. Let it happen. You are not really being hurt. When sexually abused women are told to let the system work and tolerate pornography, this is what they are being told.'

Catharine MacKinnon rests her case for women's victimisation on pornography. She believes that every piece of pornography is in itself an act of sexual discrimination, or 'harm', in its production, publication, and even private use. The rock on which this vision of pornography stands is the 'snuff movie'. By the time you get to page 25 in her little book, you will have read about snuff movies 11 times. 'This is a film of a sexual murder in the process of being committed. Doing the murder is sex for those who do it. The climax is the moment of death. The intended consumer has a sexual experience watching it . . .'

It is too easy to be enraged by these references. You will murmur in your heart, yes, it must be banned. All of it. All the men imprisoned. And then a few minutes later you will remember that the existence of snuff movies has never been proven, and that over 90 per cent of all the pornography found in this country is free from any suggestion of violence.

It takes a while to remember the arguments against her because MacKinnon is a messianic, bludgeoning preacher. She fuses legal theory, disturbing case histories, and emotive analogies, with realistic analysis of our difficult society and idealistic visions for the future. The whole is impressive, and deeply flawed. MacKinnon is frustratingly choosy in her wider terms of reference - the abused actress, Linda Lovelace, is often called as witness for the prosecution, but no women who have voluntarily participated in pornography are heard. The societies that ban pornography but refuse to raise the status of women are not considered. Nor does she confront the fact that the rise in the open sale of pornography has coincided with a rise in women's speech, not women's silence, with the rise of reporting of sex crimes and the punishment and treatment of offenders.

MacKinnon's rational arguments are almost drowned out by her rhetoric. She opens with the most overheated and tilted version of female sexual history: 'You grow up with your father holding you down and covering your mouth so another man can make a horrible searing pain between your legs. When you are older, your husband ties you to the bed and drips hot wax on your nipples . . . In this thousand years of silence, the camera is invented and pictures are made of you while these things are being done.' The desire to outrage rather than argue mars the book from start to finish: but the most cogent point she puts is that the protection given to free speech in the US (through the First Amendment) must be tempered by a commitment to equality (the Fourteenth Amendment). In discussing how one could attack pornography through a commitment to social equality, she brings in the related legal concepts of sexual harassment, group libel and - as we call it in Britain - incitement to racial hatred.

The idea of legislating on pornography from the point of view of its effects on equality, rather than its 'obscenity', might possibly be useful. To take it through to our context, it would certainly entail throwing out the outdated vehicle of the Obscene Publications Act. It might lead to greater freedom: equality of representation could be one issue, which might enable the showing of erect penises in high-street pornography, a move that many women and homosexuals would support. Or it might lead to more regulation: Clare Short's attempt to extend the Indecent Displays laws to outlaw page 3 pictures clearly arose from the desire to stem their chilling effect on women's equality rather than a desire to label women's bodies indecent; but she could find no better legal frame for it.

This shift in our attitude to pornography from something intrinsically obscene to something that has discriminatory effects, is a fascinating concept. And whether it can be put into legal or social practice is hedged about with thorny issues. But MacKinnon omits, here, to point up what is to be done. In that the whole book is a tirade against pornography, most readers have seen it as making a case for blanket censorship. What is only tucked away in a footnote is that, in the ordinances that MacKinnon and Andrea Dworkin drafted (and which were used briefly in Indianapolis and Minneapolis before being deemed unconstitutional) their famous definition of pornography was designed mainly to assist women in recovering damages against pornographers whose work could be shown to have contributed to their abuse or discrimination.

Why doesn't MacKinnon lead on such pragmatic (if just as controversial) points? Why does she ignore real possibilities for change, in favour of inflated visions? Her most worrying tendency is a totalitarian one: 'In a society in which equality is a fact, not merely a word . . . sex between people and things, human beings and pieces of paper, real men and unreal women, will be a turn-off. Artefacts of these abuses will reside under glass in museums next to dinosaur skeletons.' In the vision of an equal society which I, too, hold in my heart, that needn't be the case. The art and literature, poetry and painting, film and photography of sexuality - yes, even submissive sexuality - could still talk to us, still move us and even excite us. It is abuse, not dreams or desires, that we should try to control. We can only make ourselves better, not other. And perhaps MacKinnon, if she laid down the preacher's robe, could help us towards that better world.