If the mighty Goldman Sachs can be brought to its knees by the turmoil in world markets we really are in trouble. Lloyd Blankfein, its chairman, and the rest of its senior executives will find the idea they need outside help insulting. The favoured option will be to defy the doom-mongers, push ahead as normal and wait for the storm to clear. The risk is that Goldman then becomes the focus of rumours and the next target of the shortsellers. Every time Wall Street has a bad day, Goldman shares could be hit.