Why a central bank cannot absorb a government's debt
Video script
1. The pressure (~38 s)
There is a lot of debt in the world right now. Public debt markets are under pressure. Governments are looking for relief. Sooner or later that pressure will reach central banks.
In France, for example, Jean-Luc Mélenchon has proposed that the Eurosystem should absorb part of the French public debt.
This is dangerous. Central bank independence is not an administrative detail. It is the reason a currency exists and survives. Let me try to explain why, in simple words.
2. Money is central bank debt (~46 s)
Start with what central bank money is. When the central bank buys an asset and pays for it with newly issued money, its own stock of debt increases. In fact, money is the debt of the central bank.
But it is a strange kind of debt. The central bank will never repay it. There is no maturity, and nothing you can claim. The only value of money comes from the fact that we trust that others will accept it in exchange for goods.
But then, what is special about central bank money? Why not somebody else's debt?
3. What the central bank is for (~39 s)
We trust central bank money because of what the central bank is.
The central bank is the only institution whose objective is to keep the value of its own debt stable.
This is another way to state its mandate: keeping the purchasing power of money stable and predictable, which means pursuing price stability.
Defending the value of money and defending the value of the central bank's own debt are one and the same thing.
4. Why nobody else can promise this (~29 s)
Every other economic entity has the opposite interest.
A firm, a household, a government all want their debt to be worth as much as possible when they issue it, and as little as possible when they repay it. That incentive is universal.
The central bank is the single exception. This is why its promise can be believed, and why nobody else's can be.
5. What changes if it absorbs public debt (~54 s)
Now imagine that the central bank starts worrying about the value of somebody else's debt, let us say the government's. The whole structure of trust is at risk.
The next time you sign a contract that involves paying money in the future in exchange for goods today, you have to ask a new question: what will the central bank do if the government gets into trouble? And what would that imply for the value of central bank debt, that is, for the value of money?
Caring about the stability of someone else's debt makes it impossible to care about its own. So your contract ultimately becomes a bet on the future of the government's finances.
6. Conclusion (~41 s)
Under full central bank independence you do not have to ask these questions about the future value of money. That is the whole value of a currency: it is the one price nobody needs to forecast because the central bank is fully committed to pinning it down.
Once we start wondering about the central bank's other goals, it is no longer the same currency.
There are no shortcuts in public finance. Forcing the hand of the central bank would not make the debt go away.
It would only risk adding a far heavier monetary crisis on top of the debt crisis.