I like to think she stepped off the podium, nipped round the back and made a gagging motion with her fingers. The alternative – that Michelle Obama was unembarrassed about telling the Democratic National Convention how much more she loves her man since he became President – is simply too awful to contemplate. It's almost as awful as David Cameron's reshuffle, in which he sacked or demoted women and – this must be some kind of sick joke – appointed a Health Secretary who has voted for the time limit on legal abortions to be reduced from 24 to 12 weeks.

It's not a good time to be a woman on either side of the Atlantic. In a country where "vagina" is currently a dirty word, Michelle Obama apparently felt the need to dispel any worries about her influence on her husband by describing herself as "mom-in-chief". At least Mrs Obama talked about her husband's commitment to equality, while at Westminster the Prime Minister was busy shifting the Women & Equalities brief from the Home Office to Culture in a clear sign of its declining status. It will now be done by Maria Miller in spare moments from her day job looking after culture, media and sport.

Women are worse off after the reshuffle, despite Cameron's promise in 2008 that a third of all ministers would be female by the end of his first term in office. Just a thought, Prime Minister: how's that project going, dear?

Someone might reasonably object that the women Cameron ejected from the Cabinet – Cheryl Gillan, Caroline Spelman and Baroness Warsi – aren't very good. That's true, but just look at the men he's kept in or promoted. George Osborne, who's destroyed all hope of an economic recovery. Andrew Lansley, who's destroyed the National Health Service. Jeremy Hunt, who – where do I start? It turns out that the minister who became a laughing stock over the summer was actually doing such a fantastic job that he's been promoted to Lansley's old post. Who would have guessed?

Amid a slew of bad news for women, Hunt's appointment is one of the worst. As recently as 2008, he voted to restrict legal abortion to 12 weeks, and there's no indication that his views have changed since. Nor is he the only Cabinet minister with reactionary views on the subject. His new colleague, Maria Miller, supported an attempt by the Tory backbencher Nadine Dorries to strip counselling from abortion providers and hand it to organisations which might have an anti-abortion stance. Do I think our vaginas are safe in their hands? Not for a moment, and we now have a Government that's getting visibly more hostile to women as we head towards the next general election.

This is what happens when political parties fail to modernise. The days when Tony Blair put record numbers of women in Cabinet – five in 1997, eventually rising to eight – already seem a long way off. Even that wasn't good enough, as Ed Miliband acknowledged when he gave 11 out of 27 shadow Cabinet jobs to women. But because they have so few female candidates in winnable seats, electing a Conservative Government (or one in which they're part of a Coalition) is always going to mean a setback in terms of gender. Of 306 Tory MPs elected at the 2010 general election, only 48 were women – Labour had 81 – and the proportion of women ministers fell from 30 per cent to 17 per cent.

But systemic discrimination against women in the Conservative party has another, more insidious effect. As long as competition for seats is so fierce, it seems likely that women on the socially liberal wing of the party will continue to struggle to get selected. That means too few women on the Tory side in Parliament who will tell the Prime Minister frankly about the unequal impact of job cuts or argue for changes in policy to protect women. Female unemployment in the UK reached a 25-year high earlier this year, and that's a direct consequence of decisions taken by Cameron's male (and white, and public-school-educated) cronies.

In this atmosphere, the space for women to speak out boldly on a range of issues is becoming more restricted. It's not that I expected Michelle Obama to start a chant of "vagina, vagina, vagina" in solidarity with the Democrat who was banned from the floor of the Michigan State House for saying the word aloud. But Mrs Obama's convention speech was folksy and anecdotal, recalling the "guy who picked me up for our dates in a car that was so rusted out, I could actually see the pavement going by through a hole in the passenger-side door". It's what Sarah Brown did at Labour's 2009 conference in an attempt to humanise a husband with communication problems, and it's tragic to see centre-left parties resorting to such tactics.

I don't want speeches from politicians' wives. Nor am I calling for a day when a husband gets up to tell tear-jerking anecdotes about his brilliant wife, the prime minister. All I want – and is it really such a big thing to ask? – is more women becoming politicians in their own right.

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