More from Paul Krugman. This is from the New York Review of Books (there's much more in the original):
What to Do, by Paul Krugman, NY Review of Books: What the world needs right now is a rescue operation. The global credit system is in a state of paralysis, and a global slump is building momentum as I write this. Reform of the weaknesses that made this crisis possible is essential, but it can wait a little while. First, we need to deal with the clear and present danger. To do this, policymakers around the world need to do two things: get credit flowing again and prop up spending.
The first task is the harder of the two, but it must be done, and soon. Hardly a day goes by without news of some further disaster wreaked by the freezing up of credit. ...
Even if the rescue of the financial system starts to bring credit markets back to life, we'll still face a global slump that's gathering momentum. What should be done about that? The answer, almost surely, is good old Keynesian fiscal stimulus. ...
I believe not only that we're living in a new era of depression economics, but also that John Maynard Keynes—the economist who made sense of the Great Depression—is now more relevant than ever. Keynes concluded his masterwork, The General Theory of Employment, Interest and Money, with a famous disquisition on the importance of economic ideas: "Soon or late, it is ideas, not vested interests, which are dangerous for good or evil."
We can argue about whether that's always true, but in times like these, it definitely is. The quintessential economic sentence is supposed to be "There is no free lunch"; it says that there are limited resources, that to have more of one thing you must accept less of another, that there is no gain without pain. Depression economics, however, is the study of situations where there is a free lunch, if we can only figure out how to get our hands on it, because there are unemployed resources that could be put to work. The true scarcity in Keynes's world—and ours—was therefore not of resources, or even of virtue, but of understanding.
We will not achieve the understanding we need, however, unless we are willing to think clearly about our problems and to follow those thoughts wherever they lead. Some people say that our economic problems are structural, with no quick cure available; but I believe that the only important structural obstacles to world prosperity are the obsolete doctrines that clutter the minds of men.