On Wednesday last week, yields on 10-year US Treasuries – generally seen as the benchmark for long-term interest rates – rose above 3.73 per cent. Once upon a time that would have been considered rather low. But the financial crisis has changed all that: at the end of last year, the yield on the 10-year fell to 2.06 per cent. In other words, long-term rates have risen by 167 basis points in the space of five months. In relative terms, that represents an 81 per cent jump.
Most commentators were unnerved by this development, coinciding as it did with warnings about the fiscal health of the US. For me, however, it was good news. For it settled a rather public argument between me and the Princeton economist Paul Krugman.

It is a brave or foolhardy man who picks a fight with Mr Krugman, the most recent recipient of the Nobel Prize for Economics. Yet a cat may look at a king, and sometimes a historian can challenge an economist.

A month ago Mr Krugman and I sat on a panel convened in New York to discuss the financial crisis. I made the point that “the running of massive fiscal deficits in excess of 12 per cent of gross domestic product this year, and the issuance therefore of vast quantities of freshly-minted bonds” was likely to push long-term interest rates up, at a time when the Federal Reserve aims at keeping them down. I predicted a “painful tug-of-war between our monetary policy and our fiscal policy, as the markets realise just what a vast quantity of bonds are going to have to be absorbed by the financial system this year”.