The credibility of a woman's voice is often undermined by sexual slurs – as rape victims, Madonna and Pussy Riot well know

Every now and again the rhetoric of patriarchal power reveals itself in a way that – were it not so pernicious – one would almost call poetic.

Last week in Moscow, Madonna lent her voice to the growing international condemnation of the trial of members of the feminist performance art group, Pussy Riot. During a concert she stripped off her shirt to reveal the group's name emblazoned on her back, before donning a version of their trademark balaclava for a slow rendition of Like A Virgin.

How, we wondered, would the Russian authorities respond to this brazen act of feminist solidarity? For the deputy prime minister, Dmitry Rogozin, the answer was obvious. On Wednesday night on Twitter, he as good as called the queen of pop a whore. Madonna's benediction – as it were – of Pussy Riot was beautifully apt. The charge of "hooliganism" against three members of the group relates to the performance last February of a "punk prayer" in which they exhorted the Virgin Mary to "put Putin away".

In a recent Guardian interview, a member of the group still in hiding explained that "the main concept was to appeal to the Virgin", to ask her to "protect the political system" because "the Virgin is the protector of Russia". While superficially an act of naive superstition, one suspects the women were not really banking on their leader being summarily swept away by divine intercession. Just like Madonna before them, the insolent political power of their gesture came from self-consciously reclaiming that great emblem of patriarchal oppression. They wanted the Virgin to abandon the patriarchs, switch sides, and "become a feminist". They wanted her pussy to riot.

Against this background Rogozin's dismissal of Madonna-as-whore almost reads as inadvertent irony. The subtext is nothing if not glaring. In the patriarchal playbook, a woman's moral virtue is synonymous with … well, her virtue. Good women are chaste and pure. And the others – those who express their sexuality in ways not sanctioned by church and state, those who are sexual at all – are quite simply not to be trusted. They seduce and entrap. They're dirty and diseased. And, above all, they are deceitful and duplicitous. If they want to moralise, they should, as Rogozin told us in his second tweet, put their pants back on. And if they refuse, nothing they say is to be taken seriously or believed by anyone. A simple sexual slur, and, as if by magic, a woman's word is instantly devalued, divested of authority and discredited.

From the comfort of a purportedly post-feminist Britain, it's tempting to view Rogozin's slut-shaming as the reflexive twitchings of a tyrannical dinosaur. Certainly, Pussy Riot's shout out to the Madonna – and Madonna's equally high-profile response – have exposed a political regime that seems miles away from our own. But perhaps we should not slip so easily into self-satisfaction about dastardly oppression in the onetime land of the gulag. In everyday English, it is not uncommon to encounter the word "whore" in the company of the word "lying". And, while our liberties clearly outstrip those of Russia's citizens, many women's lives in the "free" world are still marred by the lexicon of sexual slurs used by Rogozin. By the intention to control our bodies, and our political and sexual expression, by mobilising the logic of faithful virgins and feckless whores.

One doesn't have to cast about much in our recent history to find some notable examples. One thinks of Rush Limbaugh's characterisation of the birth-control activist Sandra Fluke as a "slut", coming at a moment when American women are facing an unprecedented assault on their reproductive freedoms. Or the censuring of Michigan Rep Lisa Brown for daring to trash the "decorum" of the state legislature by mentioning women's ladybits in public. In both these cases, as with Madonna and Pussy Riot, the credibility of a woman's voice – and in particular, her resistance to patriarchal domination – was undermined not on the basis of her arguments or opinions, but because she either expressed herself sexually, or talked publicly about sex or sexual organs.

Perhaps the most sobering example of the damage done to women by consistently conjoining female sexuality with inherent untrustworthiness is our abject failure to successfully prosecute the crime of rape. The rape conviction rate is not the desultory 6% we often hear quoted, the fact remains that, according to some estimates, less than 2% of rapes committed in the UK result in a conviction.

The reasons for this are undoubtedly complex, but the prevalence of "rape myths" – most notably that women lie about rape, and that promiscuous, or merely sexually active women make unreliable witnesses – prejudices the attitudes of jurors, the CPS and the police, and discourages women from thinking it possible for them to believed. The tenor of our jurisprudence on rape was famously set by Lord Chief Justice Hale in the 17th century, whose "cautionary instruction" that "rape … is an accusation easily to be made and hard to be proved" was routinely issued to jurors until the 1980s. And in this supposedly more enlightened age, the successful prosecution of rape is still often mired in suspicions about women's credibility, or scuppered by victim's anxieties that they will be "judged … as promiscuous and unreliable".

Our continued toleration of this paltry figment of justice takes place, notably, at a time when the denizens of the men's rights movement (MRM) consider our society to be in the grip of a pandemic of false rape accusations. A site called register-her.com has created a "community resource" to register false accusers and put an end to an ill "more corrosive to civil society than any other violent crime". And, just in case you're not quite feeling the WTF?, let me spell it out – the tsunami of "corrosive violent crime" in question is not the 94,000 rapes committed in this country every year.

The MRM which sees every woman who accuses a man of rape as a liar undoubtedly represents the extreme end of a certain set of assumptions about women, their sexuality and their testimonial credibility. But their noxious rhetoric is not operating in a cultural vacuum. Any women – be it the mighty Madonna or an unknown adolescent assaulted by her partner – must, if she wants to stand against male sexual and political power, first steel herself against an immemorial question; will the fact that I have had sex mean I will not be believed?

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