I think part of this is worries about the Greek debt crisis, part of it worries about a bad retail sales number confirming some irrational exuberance about the recovery, maybe part of it worries about a newfound intensity against the big banks, but the Dow is completely falling off the cliff today. It was 900 points down a few minutes ago, though it has bounced back to a 655-point loss. And there’s still an hour to go in trading.

The Greek debt crisis is real. It’s unlikely that even the very large loan proposal and austerity package will solve it at this point – it has been allowed to spiral out of control for too long. The contagion could easily spread across Europe. There’s little difference between the popping of this sovereign debt bubble and the popping of the housing bubble. It feels at least somewhat like 2008, with banks toppling and hastily-arranged work-outs made over weekends. The damage from the financial crisis hasn’t ended. And that argues for stronger, not weaker, protections, to end the potential Depression-inducing time bomb at the heart of our financial markets.

UPDATE: Now it’s bounced all the way back to -447.

UPDATE II: There’s a rumor that this is attributable to human error. Who knows?