President Ma Ying-jeou presided Tuesday over the unusually public test firing of 19 surface-to-air and air-to-air missiles, but about a quarter missed their targets, earning his dismay and raising new questions about Taiwan's readiness to defend itself against Chinese attack. The exercise followed last week's successful test flight of China's next generation J-20 stealth aircraft, a system expected to further widen its growing edge over Taiwan's own equipment-starved air force. Ma's presence at the base in southern Taiwan where the missile test was conducted was meant to underscore his commitment to the maintenance of an effective Taiwanese deterrent, but the...