When the Federal Reserve meets today, a cut in its main short-term interest-rate target, the federal-funds rate, won't be the only thing on the table. Officials will also have to decide what action to take on the lesser-known discount rate, at which banks borrow directly from the Fed. Normally, banks pay a "penalty" to borrow from the Fed's discount window of one percentage point over the target for the federal-funds rate, at which banks lend to one another in a market heavily influenced by the Fed. Banks seldom borrow at the discount window because they can borrow federal funds more...