Taiwan’s coastguard fired a supersonic anti-ship missile during a military exercise last week, an unusual move by a civilian law enforcement agency that analysts say could be aimed at complicating potential war plans. The drill matters not only because it highlights the growing integration between the agency and Taiwan’s navy, experts argue, but also because missile-armed coastguard vessels would add another threat the People’s Liberation Army (PLA) would have to account for in a conflict. On...