Top generals have been insisting for years that if North Korea launched a missile at the United States, the U.S military would be able to shoot it down. But that is a highly questionable assertion, according to independent scientists and government investigators. In making it, the generals fail to acknowledge huge questions about the effectiveness of the $40 billion missile defense system they rely on to stop a potential nuclear-armed ballistic missile fired by North Korean or Iran, according to a series of outside reviews. "They are leading political leaders to believe that they have a military capability that they...