It is this "fiscal cliff" bit of idiotic legislation that last year's congress decided to pass as a self-incentive to reach a budget compromise beforehand, which they still have not done yet. It is basically a "doomsday device" that no one ever wanted to happen, but they've all been spending all their time trying to get re-elected rather than work on a federal budget. If they don't do something soon to resolve things, the sharp spending cuts across the board and automatic tax increases hits us all on January 1st.
Wall street (like me) doesn't have alot of confidence in the lame duck session between now and Christmas break (and they take a break for Thanksgiving too) to get anything meaningful done.
Hence, stocks are beginning the slump - and they slump alot more the closer it gets to Christmas without some hope of resolving things.
I'm sure that they'll find a way to kick the can a few months further down the road and stick it to the new congress and Obama to figure out next year. And we'll all be waiting, and unhappy.