I’ve just Googled “optimum” and “national debt” and came across a load of nonsense. So let’s try to work out what the optimum level of national debt is.
And if you want to jump to the conclusion it’s as follows. 1. Interest on the debt should be kept at zero or near zero, which effectively makes it much the same as monetary base. 2. The size of “debt plus base” should be whatever induces the private sector to spend at a rate that brings full employment, which is pretty much a re-statement of Keynes’s dictum: “Look after unemployment and the budget will look after itself”.
First, national debt and monetary base are similar in nature. For example, both are an asset as viewed by those holding debt and base. And both are a liability of the government / central bank (GCB). At least they are a liability OF A SORT.
Monetary base might not seem like a liability: after all, while a £10 note (a particular form of monetary base) says that the Bank of England promises to “pay the bearer on demand the sum of £10”, that doesn’t amount to much of a promise in the sense that you won’t get a £10 lump of gold from the BoE in exchange for your £10 note. On the other hand, it’s a characteristic of a liability that it can be used to cancel out an equal and opposite liability. E.g. if government demands £1,000 in tax from you, you can cancel out that liability with a bundle of £10 notes.
As to national debt, that’s no more than a promise by government to effectively give you a bundle of £10 notes at some point in the future.
Conclusion: both debt and base are kind of liability of GCB*.
What if the private sector has too much debt and base?
If the private sector has more debt and base than it wants, it will try to spend it away: partly on consumables and partly on other assets: the net effect will be a rise in demand. That’s sometimes called the “hot potato effect”.
But clearly that’s not desirable if demand is already at the maximum that is consistent with acceptable inflation (NAIRU if you like acronyms.)
Likewise, if the private sector has an INADEQUATE stock of base and debt, then Keynes’s “paradox of thrift” kicks in: that is people will try to save so as to build up their stock of money and/or national debt. And that means INADEQUATE demand, which in turn means excess unemployment.
So… the provisional conclusion is that the total of base and debt should be held at the level that keeps demand at it’s optimum level (NAIRU). And note that there NO SAYING what that level might be. It could be 10% of GDP or it could be 200% (as would seem to be the case in Japan at the moment - at least Japan has a debt/GDP ratio of about 200%).
Next, the amount of debt the private sector will hold depends on the interest rate offered: a relatively high rate will induce the private sector to hold more than if a lower rate is offered.
So that raises the question as to what the optimum rate of interest is. As regards government debt which is used to fund infrastructure, that would seem to be a good reason for government debt. Actually that’s debatable, and for reasons explained by Kersten Kellerman: she argues that investments made by government should be funded out of income, not borrowing.
But let’s accept the conventional wisdom, namely that incurring such debt IS JUSTIFIED. That is, let’s assume that infrastructure is funded by bonds, with the interest dependent on income from relevant investments: i.e. there is no government GUARANTEE of ANY RETURN. So those bonds and investments are treated in the same way as PRIVATELY OWNED infrastructure or other investments.
There is then the entirely SEPARATE question as to how much government debt there should be that funds CURRENT SPENDING (as opposed to the above capital spending).
Politicians like debt.
Now we all know why politicians like cutting taxes and borrowing instead: it makes politicians popular with voters (as David Hume pointed out 250 years ago – see paragraph starting “It is very tempting..”). Meanwhile, future voters / citizens have to pay back the debt – by which time incumbent politicians have retired and are making a killing out of writing their memoires and making after dinner speeches.
So the big question is: what’s the justification for funding CURRENT SPENDING out of borrowing rather than via tax? Well the answer is: “absolutely none”!!!!
Borrowing to pay your household electricty bill makes no sense. I.e. current spending should be funded out of current income.
So . . . the only real excuse for government debt is the one mentioned above, namely that it (along with monetary base) gives the private sector a stock of paper assets that is sufficient to induce the private sector to spend at a rate that brings full employment.
But there is absolutely no reason to pay the private sector INTEREST for holding that stock of assets. Ergo the rate of interest on the debt should be zero, or thereabouts (as advocated by one of MMT’s leading lights, Warren Mosler). But national debt that yields no interest is pretty much the same as monetary base.
So we seem to have reached the apparently bizarre conclusion that there is no case for government debt (except possibly to fund infrastructure etc). Or put it another way, the conclusion seems to be that if there is to be any debt, the interest offered should be so low that debt almost equals central bank issued money, i.e. monetary base.
But that conclusion is not actually all that bizarre: Milton Friedman advocated that the only liability government should issue should be monetary base. (See Friedman’s paragraph starting “Under the proposal…”).
Govt doesn’t control interest rates.
The conclusion we’ve arrived at, i.e. that interest on the debt should be kept at or near zero implies that GCB should not adjust interest rates. And that in turn imples that adjusting demand should be done only via fiscal adjustments. Now is that a problem? Well no. And for the following reason.
Adjusting demand via interest rate changes is DISTORTIONARY: that is, channelling stimulus into the economy just via investment makes no more sense than channelling stimulus into the economy just via car production and any other small selection of products (public or private sector) that you care to list at random.
What is “fiscal policy”?
I’ve glossed over an important point so far, namely the question as to exactly what “fiscal policy” consists of. What might be called “pure fiscal policy” consists of having government borrow and spend (and/or cut taxes). But that, as is widely recognised may raise interest rates, and assuming stimulus is justified then an interest rate rise is obviously not called for. So given a dose of fiscal stimulus, the central bank needs to print money and buy up enough government bonds to ensure that rates DON’T rise.
So let’s say “fiscal stimulus” is used here to refer to government borrowing and spending, with the central bank buying back sufficient government bonds to keep interest rates constant. An alternative definition would be to assume that government and central bank are effectively merged, and that £X of so called fiscal spending is funded from the printing press (a policy advocated here.)
Interest rate changes completely ruled out?
The above advocated policy might seem to completely rule out interest rate adjustments. And that is potentially risky in that it removes a tool for adjusting demand. However, there’d actually be nothing to stop the central bank, given excessive private sector irrational exuberance, from wading into the market and offering to borrow at above the going rate of interest (with the interest being funded out of increased tax).
But that’s different to traditional GOVERNMENT BORROWING. The latter borrowing funds spending. In contrast, the form of central bank borrowing described in the above paragraph simply removes money from the private sector with nothing being done with that money: completely different.
The ideal level of national debt is never achieved.
The above arguments are not supposed to suggest that given say excess unemployment, GCB should try to adjust the sum of debt and base to its ideal level IMMEDIATELY. And there is no need to because the simple fact of MOVING TOWARDS that ideal would reduce unemployment. That is, given excess unemployment, if GCB simply prints money and spends it (and/or cuts taxes), that on it’s own cuts unemployment. And the longer that “print and spend” policy lasts, there nearer the sum of debt and base gets to the ideal (assuming that the ideal has not in the meantime changed).
So what’s the optimum size of the deficit, debt and base? In just a few words . . .
The optimum sized deficit is the size that keeps unemployment at the minimum level consistent with acceptable inflation (NAIRU). That deficit will always TEND TO move the debt plus base towards a level such that full employment is maintained without any need for a deficit.
* P.S. (22nd October 2013). Just to drive home the point that the nature of national debt is elusive, here is Robert Eisner on the subject. "Everyone talks about the federal debt, but few, literally, know what they are talking about. That is all the more true for the federal deficit, which year after year adds to the total debt outstanding."