Desperate times call for desperate measures. But remember, no less, that decisions taken in haste may shape the financial system for a generation. Speed is essential. But it is no less essential to get any new regime right.

No doubt, the crisis has long passed the stage when governments could leave the private sector to save itself, with just a little help from central banks. For the US, the rescue of Bear Stearns was the moment when that option evaporated. But the events of the past two and a half weeks – the rescues of Fannie Mae and Freddie Mac, the failure of Lehman Brothers, the sale of Merrill Lynch, the rescue of AIG, the flight to safety in the markets and the decisions by Morgan Stanley and Goldman Sachs to become regulated bank holding companies – have made a comprehensive solution inevitable.

The US public expects action. The question is whether it will get the right action. To answer it, we must agree on the challenge the US financial system faces and the criteria for judging how it should be met.