I can't say that all economists are dumb. A bunch of them hanging out in Italy, including Dr. Nouriel Roubini, know all too well just how weak the world economy is going to be for a while. It's good that they're speaking in probabilities and not certainties. No one can know for certain how severe or lengthy this renewed weak period will be. Nor can anyone know whether the Fed is going to recreate its "Operation Twist" strategy from the 1960s that is supposed to push down long-term interest rates. Selling any short-duration instruments will push up short-term rates in the face of increasingly nervous European banks unwilling to lend to each other. Operation Twist is fraught with the risk of locking up overnight lending and relaunching the credit crunch.