The basic proposition of the RHT is that it is a tiny tiny tax which will raise a humongous sum of money. Nobody is really going to have to pay it – ‘coz it’s so very tiny – but if anyone does, it will be bankers. (If you think I am exaggerating go and look at the video again.) The tax may or may not be intended to reduce volatility. My tentative answer is: the RHT is a very large tax with an uncertain incidence. We don’t know who will pay it, but $400bn is a lot of money so let’s not act like it’s going to come from nowhere. It might reduce volatility but the balance of both theory and evidence is that it won’t.
I have much more confidence in my other conclusion: that the RHT campaign has little or no interest in the evidence.