Nick Cohen raises a point that has long puzzled me. He says:

As a rule you will find that the great questions of an age create divisions within the left and within the right rather than between the left and the right. In every instance, that is, except one.

The exception, he says, lies in attitudes to fiscal austerity; the right are pretty universally for it and the left pretty universally against.

I say this is puzzling because it's not obvious that there should be a strong logical connection between one's political opinions and attitudes to Keynesianism, for four reasons:

- The question of the size of fiscal multipliers is a (hard-to-measure) technical one, not a matter of political opinion. If a multiplier is 1.5 rather than 0.5, it is so whether you're a leftie or rightie.

- It's not obvious that material short-term class interests explain why Tories are opposed to Keynesianism. Fiscal expansion can be good for profits and well as jobs. And insofar as such expansion helps raise real interest rates, it's good for the retirees who form much of the Tories' electoral base.

- You can support Keynesianism without supporting big government. This was Keynes' own position. As Mark Thoma has said, "there is no necessary connection between the size of government and Keynesian stabilization policy."

- For most of the 50s and 60s, the right did subscribe to Keynesianism. It was Milton Friedman, not Richard Nixon, who said "we are all Keynesians now."

Why, then, should attitudes to Keynesianism now be split on left-right lines?

I don't think it's got much to do with attitudes to inflation. Early Keynesians were at least as hostile to inflation as monetarists were in the 70s and 80s. The authors of the 1944 white paper, Employment Policy (pdf), for example, wanted "a firm determination to keep stability in the general level of prices."

Instead, I suspect there are three possibilities. One was suggested by Kalecki - that a pro-capitalist government must reject Keynesianism, despite its short-run benefit to capitalism. in order to ensure that power over the economy remained with capitalists rather than the state over the long-run.

A second possibility lies in public choice; the right fear that Keynesianism does lead to big government, because governments find it easier to raise public spending in good times than cut it in bad.

A third possibility is that the right have become more dogmatic believers in free markets than Keynes was. Keynes thought markets were micro efficient but macro inefficient:

When 9,000,000 men are employed out of 10,000,000 willing and able to work, there is no evidence that the labour of these 9,000,000 men is misdirected. The complaint against the present system is not that these 9,000,000 men ought to be employed on different tasks, but that tasks should be available for the remaining 1,000,000 men. It is in determining the volume, not the direction, of actual employment that the existing system has broken down.

However, today's rightists cannot admit even this one failing of the free market.

I'm not sure which of these explanations, if any, is right. But whatever the explanation is, it'll have to be very powerful to explain why the left-right distinction is so closely connected to the pro- and anti-Keynesian distinction.