Suddenly, the term "too big to fail" is off the table. With Lehman Brothers likely to go into bankruptcy, Wall Street is preparing for a very rocky trading day. We'll get a hint of what's in store in a few hours when Asian markets open for business. Already, there's been an emergency trading session at the International Swaps and Derivatives Association to "reduce risk associated with a potential Lehman Brothers Holdings Inc. bankruptcy." The ISDA was allowing customers to make trades and unwind positions linked to Lehman. The problem is that the financial world is inexorably intertwined - so much so that trying to decouple may prove perilous.