Investors don't seem very optimistic that the economy will be helped out by the buying and selling of securities - what the Fed calls "Operation Twist." From the WSJ:
"The twist is like a popsicle when you have a sore throat -- it makes you feel good but it doesn't address the underlying disease, and the disease is confidence, not that liquidity is too expensive," said Ron Florance, managing director of investing strategy and asset allocation for Wells Fargo Private Bank. "The Fed has been as accommodative that it can, and now it's the other side of the balance sheet that needs to make a longer-term prudent fiscal policy...The super-committee on the budget is really the one that people are waiting for now."
The other problem is that so much of the market action these days centers on Europe, and there's not much the Fed can do about that. The Dow wound up losing 283 points, to 11,124, most of that late in the day.