Ever since a student was brutally gang-raped in Delhi in 2012, there has been a steady stream of reports about horrific sexual violence in India. In the most recent incident, two young sisters in the impoverished state of Uttar Pradesh were found hanging, dead, from a tree, after being gang-raped.

Like the assault in Delhi – when the victim later died from her injuries – the case has prompted an outpouring of public anger and revulsion. Like the assault in Delhi, the political response has been, at best, patchy, and at worst, outright offensive.

Last week, the home minister, Babulal Guar – a member of the newly elected Bharatiya Janata Party (BJP) – caused outrage when he said that rapes were “sometimes right, sometimes wrong”. A few days later, a regional BJP minister, Ramsevak Paikra, responsible for law and order in Chhattisgarh state, said: “These kinds of incidents [rapes] happen accidentally”. Police fired water-cannons to disperse protesters outside the office of Utter Pradesh state chief minister Akhilesh Yadav, which hardly suggests that their concerns are being listened to. Narendra Modi, recently sworn in as prime minister after a landslide victory, has so far remained silent on the rape and murder of the sisters.

Of course, poor political responses to sexual violence are nothing new for India. The defence lawyer in the Delhi rape case said at the time: “I have not seen a single incident or example of rape with a respected lady”. In another case in Dwarka earlier this year, the judge said that "girls are morally and socially bound not to indulge in sexual intercourse before a proper marriage, and if they do so, it would be to their peril and they cannot be heard crying later that it was rape." Such statements are so numerous that one Indian news website keeps an ironic tab of “reasons India’s women get raped”.

Ministers can retract their statements – but such apologies do not address the reasons that these statements are made: namely, a regressive attitude to women and their sexual, social, and political rights. Gender-based violence in India starts before birth. Gender-selective abortions and female infanticide means that the male-to-female population ratio is now 0.93 (worse than in 1970); something which certainly does not help to alleviate sexual assault. There are extremely high rates of child marriage, teen pregnancy, and domestic violence. Worryingly, many see this as the norm. A 2012 report by UNICEF found that 57 percent of Indian boys and 53 percent of girls between the ages of 15 and 19 think wife-beating is justified.

In the aftermath of the Delhi rape case, lawmakers significantly tightened up laws on rape, increasing penalties and broadening the criteria of sexual assault crimes. This was a positive step – but, of course, enforcing such laws in the face of wildly misogynistic and understaffed police forces is another matter altogether. Two police officers are among the five people detained over the murder of the two sisters.

Translating public protest into lasting change is a serious challenge in any country in the world. It is particularly difficult in a country as huge as India, where joined-up policy making of any sort is a challenge, where conservative cultural traditions are upheld by the majority, and where poverty and structural violence proliferate.

Because the latest attack happened as Modi took power, some have seen it as a test of his government’s seriousness about promoting women’s rights. Modi dedicated his swearing-in speech to the "safety and security of the mothers and sisters, those in the rural areas,the oppressed and the deprived". But, although rhetoric around women’s empowerment is now firmly on the agenda, practical improvements are rarely specified, and implementation remains poor.

This is hardly unique to Modi or the BJP; it is a problem that goes beyond party politics to deep seated cultural prejudices about the place of women. But it is an urgent issue. Street harassment of women is routine and constant. According to the National Crime Records Bureau, reported instances of rape have gone up tenfold in the last 40 years.

"We say no to the dismissive, destructive attitude of, 'Boys will be boys'," said UN Secretary General Ban ki-Moon last week. Offensive statements by politicians are not the most serious part of the problem, but they do illustrate a major stumbling block to enforcing major change – both to the legal framework around rape, and to people’s mindsets.