Paul Krugman in the New York 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. As I was writing this, for example, reports were coming in of the collapse of letters of credit, the key financing method for world trade. Suddenly, buyers of imports, especially in developing countries, can't carry through on their deals, and ships are standing idle: the Baltic Dry Index, a widely used measure of shipping costs, has fallen 89 percent this year.
What lies behind the credit squeeze is the combination of reduced trust in and decimated capital at financial institutions. People and institutions, including the financial institutions, don't want to deal with anyone unless they have substantial capital to back up their promises, yet the crisis has depleted capital across the board.
The obvious solution is to put in more capital. In fact, that's a standard response in financial crises.
More here.