Emma Burnell says that politics has to be about morality. I'm not sure, for at least four reasons.

1. Morality is weak against power. If there is any moral truth at all, it is that the mass murder of innocent civilians is wrong. But when it happens, the 'international community' does nothing to stop it. Stalin's famous sneer - 'The Pope! How many divisions has he got?' is true.

On a more prosaic level, a similar thing is true of bosses' pay. A periodical fit of morality might stop one or two individuals from taking their bonuses. But a serious and systemic reduction in bosses' pay requires a shift in the balance of class power.

2. Policies are often a mix of morals. Take for example the welfare cap. Is this moral, because it stops feckless scroungers fleecing the tax-payer? Or is it immoral because it threatens to make children homeless? Morality alone does not adjudicate. The issue is about the facts of the policy or about how the issue is framed.

3. Morality can distract us from structural explanations, and hence serve a conservative function. Take for example someone who doesn't want to work. He might look like one of the undeserving poor. But is he? It could be that his 'laziness' is an endogenous preference. Surrounded by mass unemployment - and perhaps brought up amidst it - he believes there's no chance of work and so he adapts his wants to his circumstances. Is he undeserving or not? Again, morality does not adjudicate.

4. 'Morality' just poses unresolved questions. Take high pay. Is this unfair because it betokens inequality, or is it fair because it represents (in the unsubsidized economy) a free and voluntary exchange between individuals? Adjudication is a matter of moral debate; those leftists who think it isn't miss the point.

But as Alasdair MacIntyre pointed out, we have lost the faculty for such debate with the result that our moral judgments are little more than emotivist spasms.

There is, though, an alternative here. The left should appeal more to efficiency. For example, the problem with bosses' pay and bonuses is not that they are unfair, but that they are economically inefficient and the product of power, not merit. And, I'd add, the structure of capitalism - at its current juncture - is inefficient, not (just) unfair.

In this sense, Emma is missing something. She's right to want an alternative to a managerialism which tries, feebly and ineffectively, to work within the confines of capitalism. But the alternative is not a moralism which threatens to keep the left within a ghetto of impotent self-righteousness. There is a third possibility - Marxism.