The financial markets have taken the world economy hostage. This has presented the world's central banks with a dilemma. They fear the consequences of paying off those responsible for the mess. But they cannot let hundreds of millions of innocents suffer. Last week's announcement of the first US monthly fall in employment for four years has made a cut in interest rates from the Federal Reserve this month a virtual certainty. So act it will. But making the right decisions is going to be hard.

Martin Feldstein of Harvard University put the case for big cuts in a powerful summing up at this year's Jackson Hole monetary conference.* He argued that the US housing sector was at the heart of three interrelated events. First was "a sharp decline in house prices and the related fall in home-building that could lead to an economy-wide recession". Second was "a subprime mortgage problem that has triggered a substantial widening of all credit spreads and the freezing of much of the credit markets". The third was "a decline in home equity loans and mortgage refinancing that could cause greater declines in consumer spending".