For years, the International Monetary Fund helped to ensure global financial stability. Lately it has changed its mind on what used to be a core principle — and, strangely enough, it appears to have done so on the basis of a single far-from-convincing working paper.

The IMF is probably the most powerful international organization in the world. It has been effective not just because of the resources at its disposal but also because it has focused on one issue: financial stability.

Critics pay it a backhanded compliment when they say its initials stand for, "It's mostly fiscal." In fact, when it comes to the crises that the IMF is asked to manage, it really is mostly fiscal. If the IMF forgets that, it becomes part of the problem.