J. Christopher Callaghan, the Republican candidate for New York State comptroller, has a secret friend. “I don’t know his name,” Mr. Callaghan said in an interview. But one thing is clear: For some reason, he said, the person clearly despises his opponent, the incumbent, Alan G. Hevesi, a Democrat. It was this secret friend who whispered rumors to Mr. Callaghan that Mr. Hevesi’s wife was being driven around by a state employee at taxpayer expense. When Mr. Callaghan made the charges public last week, his long-shot candidacy was given new life, and Mr. Hevesi was forced to apologize. The comptroller...