U.S. officials are privately pleased by North Korea’s seven missile launches last week, as they highlighted the danger posed by the communist regime in Pyongyang and the need for missile defenses. The missile launches were carried out with no advance warning and were fired into a commercial air corridor used by numerous trans-Pacific airlines. One of the missiles crossed the flight path of a South Korean Asiana Airlines jet shortly before the plane passed through the area off the Russian coast of the Sea of Japan. U.S. defense officials said the missile launches were an impressive show of joint missile...