Happiness isn't the only thing we care about and it's not the only consideration worth according weight to in our deliberations. To make it the one and only consideration that counts—to use happiness the way Mr Layard wants to use it—would require the abolition of democracy. But the happiness data clearly show that the happiest places on earth are democracies. Thus it would seem that Mr Layard is bound by reason to abandon either his dreams of "rational public policy" determined by "a single criterion" or his allegiance to happiness as the single criterion.Well, no. Even if one accepts that democratic governance is a good idea, someone still has to be right and someone has to be wrong. It could be the case – and I think it is the case – that attempting to institute a dictatorship of utilitarian technocrats who issue laws based on the hedonic calculus will actually produce less happiness than our current system of government does. But it could simultaneously be the case – and again, I think it is – that the best policies that our democratic system can adopt are those supported by a utilitarian calculus. It then follows that utilitarians acting within the context of a democratic system should push for policies that utilitarian reasoning supports and oppose those it doesn't.
This, I think, is what Layard is saying. Declaring that non-utilitarian thinking doesn't make for "rational public policy" is an inflammatory piece of rhetoric, but it's basically a more testy way of saying that utilitarianism is going to produce the right answers and non-utilitarian theories are going to produce the wrong answers. And obviously, most people participating in a public policy debate think they have the right answers. That's how it should work: people throw out their arguments, elected representatives weigh those arguments and vote, and participants in the debate agree that it's better for that result to be binding than not. Similarly, I think moral absolutists who argue for an inviolable rule against torture are participating in a healthy debate about that issue, and aren't just crypto-autocrats who want to impose their civil libertarian views by any means necessary. It seems like only utilitarians get accused of latent dictatorial tendencies when they argue for what they believe in.
P.S. This is a side note, but rereading Wilkinson's last fight with Layard brought mere here, where Wilkinson calls "Benthamese" to be "the vulgar dialect of the morally insensate (economists, Asperger’s cases, etc.)" which gave this Asperger's-diagnosed Benthamite a good chuckle. Pretty sure I'm not morally insensate, but I'm not one to take offense at such things.