It says a lot about the talents of John Maynard Keynes – and just as much about the shortcomings of modern macroeconomics – that when the financial crisis struck, policymakers instinctively reached not for their fancy models, but for the Keynesian idea of fiscal stimulus. These pages have been filled with eminent thinkers arguing over whether it is time to bring the stimulus to an end.

Perhaps we should turn the question around: if stimulus were to be the solution, what would be the problem? The problem would be that too many of us wanted to save money or pay off debts; that is, we wanted others to pay for our services but weren't so keen on paying for theirs right now. Simple arithmetic suggests this would leave slack in the economy. In addition, the problem would be that businesses, pessimistic about prospects for recovery, didn't harness all the spare savings floating around and plough them into new investment projects. The slack would stay slack, possibly for a long time. If that was the problem then government stimulus would be the solution.

And the above paragraph doesn't seem to be a bad description of the US or UK economy, which suggests the case for stimulus is strong. True, the patience of the bond markets is surely not boundless (and say what you like kowtowing to the markets, if we'd like them to lend us money we have good reason to care whether they are willing to lend it). And there already is an awful lot of stimulus spending going on right now, so it's not absurd to suggest we could get by with less as the economy bounces back. I realise that I am sitting on the fence here, but it's part of my new maxim, which is never to stand in the middle of a fight between Paul Krugman and Niall Ferguson.