This was truly one of the most incredible days in Wall Street's history (and despite what Felix Salmon says, this isn't hyperbole). Once the news started coming fast-and-furious, it was a chore just to keep up. "Barclays pulls out! Lehman to file bankruptcy! BofA is buying Merrill! The Fed is turning the PDCF into a shadow repo market! Ten biggest banks pool $70 billion for private liquidity fund! Oh my God: AIG is collapsing, and asking the Fed for help!" Tomorrow will be chaos. No one knows how bad it'll be, since we've never experienced anything like this before, but one thing's for sure: it will be a wild, wild day. No single index will capture all the craziness, but I'll be paying the most attention to CDS spreads, along with currencies. Fair or not, this week will be a referendum on the Bear Stearns bailout. If Lehman is dismantled in an orderly manner, and financial markets hold up relatively well, then it will become conventional wisdom that the Bear Stearns rescue was a mistake. If, on the other hand, financial armageddon ensues, then the government's refusal to bail out Lehman will, obviously, be viewed as a huge mistake. The two situations aren't nearly analogous enough to make a direct comparison appropriate, but time has a way of glossing over those differences. Oh yeah, and pundits have a way of glossing over these kinds of differences too. Let the games begin.