Late last month, Japan’s defense ministry made an unsettling announcement. A U.S. ground-based missile system, known as the Typhon and capable of firing Tomahawk missiles, would not return to the United States after being deployed to Japan for military exercises. Instead, it would be stored at Kadena Air Base in Okinawa, at least temporarily.Tokyo tried to downplay the move, noting that the decision was intended to support training, not warfight…