Because apparently all he has to do is follow Gordon Brown. Here's Gordon to David Cameron during PM's questions today --
I believe that the indication that President Obama has given in the past few days that he will take the fiscal stimulus action that we have taken, and action in relation to banks in the way that we have done, shows that the world can work together to deal with the problem.
It's an especially amazing claim given that Gordon's initial approach to the banking crisis -- although praised to high heaven by Paul Krugman -- was just capital without any asset resolution or day-to-day managerial control, and the equally vaunted fiscal package in the Pre-Budget Report already looks like a dead duck. Maybe President Obama might want to take up these claims of Gordon when they meet in London in April.