The kind of economic trouble that Asia experienced a decade ago, and that we're all experiencing now, is precisely the sort of thing we thought we had learned to prevent. In the bad old days big, advanced economies with stable governments-like Britain in the 1920s-might have had no answer to prolonged periods of stagnation and deflation; but between John Maynard Keynes and Milton Friedman, we thought we knew enough to keep that from happening again.