In the textbooks it is suggested that Keynesian economics is what happens when ‘prices are sticky’. Sticky prices sound like prices failing to equate supply and demand, which in turn sounds like markets not working. Hence whether you believe in Keynesian theory depends on whether you think markets work, so it obviously maps to a left/right political perspective.
Reality is rather different. Suppose we start from a position where firms are selling all they wish. Aggregate demand equals aggregate supply. If then aggregate demand for goods falls, perhaps because consumers or firms are trying to rebuild their balance sheets after a financial crisis, producers of these goods will start to reduce output, and lay off workers. The idea that they would ignore the fall in demand and just carry on producing the same amount is ludicrous. So output appears to be influenced by aggregate demand at least in the short run, which is at the heart of what most economists think of as Keynesian theory.
So where do sticky prices come in? Here we have to go back to the textbooks, and to an imaginary world where the monetary authority fixes the money supply. Firms, in an effort to stimulate demand for their goods, cut prices. Lower prices mean people do not need to hold so much money to buy goods. However if the nominal money supply is fixed, interest rates will fall to encourage people to hold more money. The textbooks encourage us to think of a market for money, with interest rates as the price that equates supply and demand. Lower interest rates provide an incentive to consumers and firms to increase demand, which in turn raises output.
Now suppose that firms carry on cutting prices as long as they are selling less than they would like. The process just described will continue, with interest rates getting lower and aggregate demand rising in response. The process stops when firms stop cutting prices, which means aggregate demand has increased back to its original level. Suppose further that prices adjusted very quickly. This mechanism would work very quickly, so we would only observe aggregate demand being below supply for very short periods. If prices were extremely flexible, we could ignore aggregate demand altogether in thinking about output. Hence aggregate demand matters only if ‘prices are sticky’.
Note that this correction mechanism is quite complex, and some way from the simple microeconomic world of the market for a single good. But we need to move back to the real world again. Monetary authorities do not fix the money supply; they fix short term interest rates. So they are directly in charge of the correction mechanism that is at the heart of this story. If central banks had some way of knowing what aggregate supply was, and also had perfect knowledge of aggregate demand and how interest rates influenced it, they could make sure aggregate demand equalled supply without any need for prices to change at all. Equally, if prices were very flexible but the monetary authority always moved nominal rates in such a way as to fail to stimulate aggregate demand, aggregate demand and therefore output would not return back to equal aggregate supply. Demand would still matter, even with flexible prices.
Once you see things as they are in the real world, rather than as they are portrayed in the textbooks, the importance of aggregate demand (and therefore of Keynesian theory) is all about how good monetary policy is, and not about sticky prices. If monetary policy was perfect, then Keynesian theory would only be used by central banks in order to be perfect, and everyone else could ignore it. Of course for many good reasons monetary policy is not perfect, and so Keynesian theory matters.
We could re-establish the link between Keynesian theory and price flexibility by assuming the monetary authority follows a rule which would make policy perfect if and only if prices moved very fast, but the key point remains. The importance or otherwise of Keynesian theory depends on monetary policy. It is not about market failure. Keynesian economics is not left wing, but it is about how the economy actually works, which is why all monetary policymakers use it.
It is also common sense, which is why I’m often perplexed by those who dispute Keynesian ideas. Now maybe they are confused by the strange world portrayed in textbooks, but even if they think it is all about ‘sticky prices’, the evidence that prices are slow to adjust is overwhelming, so it is hard to dispute Keynesian theory on those grounds. Yet a whole revolution in macroeconomic theory was based around a movement that wanted to overthrow Keynesian ideas, and build models where this correction mechanism I described happened automatically. The people who built these models did not describe them as assuming monetary policy worked perfectly: instead they said it was all about assuming markets worked. As a description this was at best opaque and at worst a deliberate deception.
So why is there this desire to deny the importance of Keynesian theory coming from the political right? Perhaps it is precisely because monetary policy is necessary to ensure aggregate demand is neither excessive nor deficient. Monetary policy is state intervention: by setting a market price, an arm of the state ensures the macroeconomy works. When this particular procedure fails to work, in a liquidity trap for example, state intervention of another kind is required (fiscal policy). While these statements are self-evident to many mainstream economists, to someone of a neoliberal or ordoliberal persuasion they are discomforting. At the macroeconomic level, things only work well because of state intervention. This was so discomforting that New Classical economists attempted to create an alternative theory of business cycles where booms and recessions were nothing to be concerned about, but just the optimal response of agents to exogenous shocks.
So my argument is that Keynesian theory is not left wing, because it is not about market failure - it is just about how the macroeconomy works. On the other hand anti-Keynesian views are often politically motivated, because the pivotal role the state plays in managing the macroeconomy does not fit the ideology. Is this asymmetry odd? I do not think so - just think about the debate over climate change. Now of course it is true that there are a small minority of scientists who do not believe in manmade climate change and who are not politically motivated to do so, and I’m sure the same is true for Keynesian theory. But to claim that the majority of anti-Keynesian views were innocent of ideological preference would be like – well like trying to pretend that monetary policy has no role in stabilising the business cycle.
There are of course many differences between climate change denial and anti-Keynesian positions. One is the extent to which the antagonism has infiltrated the subject itself. Another is the extent to which the mainstream wants to deny this influence. I do wonder if the unreal view of monetary policy that remains in the textbooks does so in part so as to not offend a particular ideological position. I do know that macroeconomics is often taught as if this ideological influence was non-existent, or at least not important to the development of the discipline. I think doing good social science involves recognising ideological influence, rather than pretending it does not exist.