Well, yes, but there is a limit. For debt, though eminently useful at times, is also a brutal taskmaster. Share values may rise and fall, but when the music stops you are left still holding your debts. All the crises in recent years have involved countries in which debts were run up to excessive levels which then, when circumstances suddenly changed, caused acute pain. The most recent crises were in the emerging markets. Now, however, two rather larger countries look vulnerable: Japan and America.