Jeremy Corbyn's belief that the sex industry should be decriminalized should remind us of an important point - that genuine freedom requires equality.

Instinctively, I agree with Corbyn for the Millian reason that it's no business of the state what consenting adults do in private, and that as little power as possible should be given to bullies and incompetents.

This, though, runs into a counter-argument - that, in prostitution, the parties are not consenting: Harriet Harman says prostitution is "exploitation and abuse", Julie Bindel that it is " one of the most exploitative industries on the planet."

There are two parts to this claim. One is that decriminalizing (pdf) the sex trade would increase trafficking and child prostitution. However, all decent people should agree that these should have no part in the "legitimate commerce" of the sex industry. The solution to them is to forcefully uphold existing laws. The history of criminalizing the drink and drug trades surely shows us that you don't clean up an industry by criminalizing it. People are sometimes trafficked to work as slaves on farms but nobody thinks the solution to this is to criminalize farm labour.

The second part of the claim is that women are compelled into prostitution by poverty or abusive partners, and that the sex trade is exploitative. As Mary Sullivan and Sheila Jeffreys write (pdf) of the legalized sex industry in Victoria, Australia:

Women are thus forced to experience exploitation on the streets, illegally, or from sex "businessmen" in brothels. For women in legal brothels, managers and owners demand up to 50% to 60% of takings.

Here, though, is the thing. I - and I, strongly suspect, Mr Corbyn too - favour legalization of the sex industry in the context of other policies that empower women to reject exploitation. For me, these include full employment policies to give them other career possibilities; a mass housebuilding programme to reduce rents; and - of course - a basic income to improve their outside options. (A basic income could be seen as part (pdf) of a feminist policy programme.) They could also include better education not just to equip women for non-sex work, but to enhance their self-esteem and confidence and hence their ability to walk away from abusive partners.

The point here broadens. There is a big difference between capitalist freedom and egalitarian freedom. The former entails the freedom to exploit, the latter gives people the real freedom to reject exploitative job offers. It's for this reason that I have argued that genuinely free markets require Marxian policies, because a rough equality of bargaining power is necessary for legitimate commerce.

Some feminists such as Ms Bindel might reply that under such conditions, prostitution would disappear as women choose other options. Maybe, maybe not. I say: let's find out.

Another thing: Some would object to the sex trade even under these conditions as it is, in Ms Bindel's words, "vile". For me, this is no more a case for criminalizing the sex trade than the fact that some people still find homosexuality vile is a case for criminalizing gay sex. I would, however, fully endorse Ms Bindel's freedom to remonstrate against the trade, and even to try to raise the stigma against buying sex - though I disagree with her.