At a New York restaurant overlooking Central Park in April 2006, the governor of Pennsylvania sat down to dinner with about a dozen Democratic supporters. The 10-course meal in a private room at Per Se, including dishes like Nova Scotia Lobster Tail "Cuite Sous Vide," cost about $18,000, says a diner who was there. The host, Norman Hsu, was a businessman that the crowd admired but knew little about. In the past few weeks, much more has become known about Mr. Hsu: That he had filed for bankruptcy twice, including a time in 1990 when he said he had no...