More heroin or is it time for methadone – or even cold turkey? When it comes to ending stimulus packages, policymakers appear unsure. Politicians – and among them let us include Dominique Strauss-Kahn, managing director of the International Monetary Fund and former finance minister of France – want to keep the stimulus coming. “Exiting too early is costlier than exiting too late,” he said this week. This is a politician's classic position: reluctant to make an irreversible decision that will have unforeseeable consequences, and thus kicking the ball down the field.

Then there are more technically minded policymakers such as the governors of the European Central Bank. They believe that keeping the stimulus coming could create the next crisis. They are slowly switching the patient to methadone.

Developed-world governments face huge borrowing needs. So politicians naturally want to keep interest rates and bond yields as low as possible for as long as possible. For the moment, investors are helping. They continue to buy government bonds. Last week, they even bought 90-day US bills with negative yields – although that is less a strategic investment decision than a tactical need to park cash in a safe place before the year's end.