A lifetime ago, when William Jefferson was just a plain old congressman, not the central figure in what's shaping up as a major investigation of his business dealings, I sat down to talk to him about one of his pet subjects, international trade. Jefferson kicked it off by asking whether I was familiar with the Central American Free Trade Agreement. Having skimmed a stack of newspaper clippings on the subject, I told him, with utter confidence, that I was. Big mistake. Before long he was off on a treatise about trade deals past, with a particular focus on provisions to...