Vernon Lamar Jackson and William J. Jefferson and their wives spent a pleasant weekend in New York City in the fall of 2004. The Kentucky businessman and the Louisiana congressman watched U.S. Open tennis from an air-conditioned corporate box, attended The Lion King on Broadway and did a little shopping. Rep. Jefferson and his wife had become trusted friends of the Jacksons. In e-mail messages and telephone calls, the congressman was simply "Jeff." The cord that tied the two men was their stated opinion that Jackson's high-tech company, iGate, was going to save the government money and give poor black...