Behind every successful drug syndicate lies a complex mechanism for recycling bundles of tainted cash into respectable assets. But until two years ago, when Los Angeles narcotics officers seized three Zurich-bound suitcases stuffed with $2 million in currency, there was little hard evidence to implicate the venerable granite-walled banks of Switzerland in such schemes. Since then Swiss banks have been chastened by the disclosure that their accounts were used in a billion-dollar money-laundering operation. The resulting political scandal, in which the Justice Minister was forced to resign, ranks as the worst in modern Swiss history.
In response, the Swiss government has...