The current crisis has changed the rules of the economic game. Some old tricks, however, are still useful. This week, the Bank of England, the European Central Bank and the Swedish Riksbank all made dramatic rate cuts. Fiscal stimuluses are being proposed around the world. It is a measure of how damaged the global economy is that these steps will not revive it. But they are potent measures; their impacts will be widely felt.

The right approach to coping with the downturn is to buoy up demand. The main tool to this end, lowering interest rates, reduces the returns on hoarding money and makes it cheaper to borrow and to service existing debt. Large-scale debtors around the world, notably homeowners on variable rate mortgages, may now find that they are suddenly flush with cash.