The financial crash of ten years ago was something of a paradox for conventional economists. It took most of them by surprise, and dented their reputation. And yet economists became more important than ever to the running of our world. But now, to listen to most of them, the equivocation is over. We're back to normal, as the global economy looks in much better shape. This looks complacent.
The crash was a double shock to economists. The first was how it happened at all, when most economies seemed to be purring on at a relatively steady rate of growth (often referred to as the trend rate), which seemed to relate to growing productivity, and which most economists, driving through the rear-view mirror, assumed to be a law of nature. The second shock was that developed world economies, especially the British one, were so slow to recover. Economists simply assumed that with a bit of stimulus, economies would not just return to trend growth, but make up for lost ground too. I don't think any advanced economy has done this - and in Britain we lag far behind. In the years after the crash an expression was coined, or rather resurrected, to describe this second problem: secular stagnation.
The person whose name is most attached to this is Lawrence Summers, who had been prominent in the Clinton administration. By it he meant that economies could only achieve growth by extraordinary and unsustainable efforts to stimulate it. And, as Mr Summers recently pointed out in the FT, you cannot say that it has disappeared. Growth has returned, but the measures required to produce it are unsustainable. What he is referring to is the extraordinarily low interest rates prevailing in the developed world.
This has been going on for so long that we have become accustomed to it. But what do negative real interest rates mean? They mean that in order to use up available savings we have to create investments that have little or no financial return. Now that is at the margin, not on average, but even so it does not suggest an economy that is at all healthy. If investments don't produce a return, productivity will not advance, and growth will not be sustained. And in particular we will accumulate debt that cannot be paid off. Or not without inflation which destroys the accumulated wealth of the middle classes. And sure enough, many economists are warning us about mounting debt levels. In due course this will lead to a financial crisis.
Why are we in this situation? And what can we do? There are many speculations as to why, and most commentators, including me, tend to gravitate towards the one that suits their overarching narrative. Many blame a skewed distribution of income for creating a surplus of savings that cannot be used properly. Others say that modern businesses don't need so much traditional capital (Google doesn't need to issue debt or share capital to keep its investments going). Then there is the gradual ageing of the population reducing the size of the workforce. Others blame the wrong sort of stimulus - if only government spending hadn't been cut back ("austerity"), we'd have bounced back in no time. My favourite is the Baumol effect which suggests that we are in a transition towards industries, like healthcare, that are less financially productive, though still improve human wellbeing. Whatever it is (and it could be all at once) it's a problem because it is dragging down the potential growth rate.
And what can we do? People often talk of unconventional policies, but what are they? The most interesting idea is to run up bigger government budget deficits. Piling up government debt is much safer than piling up private debt, as we are doing now. Why? Because governments can finance that debt by a process that is usually referred to as creating money, and the burden can be shared more equitably.
But piling up debt and creating money often ends in tears. The best current example of that is Argentina, with rampant inflation and impatient foreign creditors. The problem for Argentina is that its monetary system has been mismanaged for so long that much borrowing, public and private, has to be in foreign currency, which the central bank cannot create. But there is an opposite example. Japan has been piling up public debt for decades, and the central bank has been buying up debt, with few apparent ill-effects.
So how do you know whether you are Japan or Argentina (and no doubt Argentina looked like Japan once)? The first, obvious, difference is that Argentina has had a current account deficit for some time, while Japan has generally been in surplus. That means that Argentina is importing more than it exports and requires financing by foreigners - who are less likely to be happy to take payment in domestic currency. Current account deficits usually flow from budget deficits - though not always, as the recent crisis in Spain showed. That would be a bad sign for countries like Britain that also have a current account deficit. But Britain's standing in international markets looks a lot more like Japan's than Argentina's. The government has no trouble in borrowing in sterling, and the same goes for most British businesses.
So why are we in Britain so worried about budget deficits and debt? One explanation is that we have been persuaded into this view by malign political forces who use the analogy of household financial management to make their case. But there are deeper worries. The first is how do you tell when you have gone far enough with budget deficits and need to stop? The traditional economists' answer is when inflation starts to take hold. But it might be too late by then, and anyway it is not so clear that in a modern, globalised economy inflation works in quite the way economists think. You know it is too latewhen there is a rush of people trying to change domestic currency into foreign, creating a panic and to people, including the government, having to borrow in foreign currency. That can happen without inflation.
The problem behind that is the politics of it. Opening up the possibility of more government spending is a huge boost to the power of central government politicians, who do not have strong incentives to apply the brakes when they need to - any more than those bankers did before the crash of 2008. It is too easy to believe your own hubris. I think this happened to the Labour government in the mid 2000s when the government should have started to tighten spending but decided not to. This didn't cause the financial crisis, but made it harder than it should have been to manage. Even now, though, it is impossible to get anybody on the political left to accept that. It's the one thing that unites Jeremy Corbyn with Tony Blair.
Still, we should be able to find ways increasing government borrowing that helps stimulate demand more sustainably. Building public housing is one idea. Other infrastructure policies should help (but not all of them). There's also a case for taking a longer view on some public spending, like education , community policing, mental health services and public health that heads off future trouble. But not building more navy frigates or, even, hospitals. We might need these, but they need to be securely funded by current taxes. The trick politically is to create a system of checks and balances that lets you invest productively and not let central government managers run away unchecked.
Behind this lies an important but rarely acknowledged idea. It is that, in the 2010s and onwards, public investment is often more productive than private investment. And that, I think, is one of the causes of secular stagnation. So in the developed world we need more public investment, and that we can afford to borrow much more to pay for it than most people think. And we need less private investment, much of which is wasted on asset recycling schemes that will end in tears. It may well take another financial crisis before we start to realise this.