Too bad Dr. Lee Bollinger, who has a law degree, forgot an essential cross-examination principle: Never ask a hostile witness a question you don't already know the answer to. If he'd remembered that bit of courtroom wisdom before he invited Iran's president to Columbia University, perhaps jihadists around the world wouldn't be laughing at America right now. Bollinger is the president of Columbia, which invited Mahmoud Ahmadinejad to a question-and-answer forum on campus this week. The showdown was supposed to expose the Iranian propagandist, but it turned out to be the biggest public relations disaster in the history of American...