On a quiet day on Capitol Hill two years ago, an apparently innocuous piece of legislation completed its journey through Congress and was shortly signed into law. The Bank Secrecy Act, yawningly endorsed by many bankers, was intended to help the Government curb tax cheaters and Mafia magnates by reducing the illegal flow of money to foreign banks. At the time there was almost no opposition to and precious little interest in the law. Today it is at the center of banking's biggest brouhaha in years.
In a desperate fight to quash the law, leaders of the banking establishment have...