There's been talk of a potential failure of Lehman Brothers for months, and the investment bank already had a near-death experience in 1998. Merrill Lynch has been labeled takeover bait for two decades. Insurers do go under from time to time. But throw together the collapse of Lehman — the biggest-ever U.S. bankruptcy — the lightning takeover of Merrill Lynch by Bank of America, concerns that giant insurer AIG is now on the brink as well, and a financial crisis that has been rolling along for more than a year now, and you get a day that will be enshrined in the history books. Whether it will go down as an economy-shattering debacle or a near miss is something we'll only figure out over the coming days and weeks. The initial reaction of U.S. stock markets — down sharply but far from disastrously at the open on Monday — is that it's the latter. But who knows?