Mattis wanted to send a third aircraft-carrier group to the Persian Gulf earlier this year, The Daily Beast has exclusively learned, in what would have been a massive show of force at a time when Iranian military commanders were publicly threatening to sink American ships in the Strait of Hormuz. The four-star Marine Corps general and CentCom commander believed the display could have deterred Iran from further escalating tensions, according to U.S. military officials familiar with his thinking. But the president wanted to focus military resources on new priorities like China, and Mattis was told a third carrier group was...