Wall Street Journal:
China and Russia are publicly lobbying South Korea to reject a U.S. plan to base a new missile-defense system on the peninsula. So far Seoul has rejected this challenge, but strong currents within the opposition favor a closer relationship with China over the U.S. The decision on missile defense is a test of the U.S.-South Korea alliance and American influence in Northeast Asia.
Seoul needs the U.S.-built Terminal High-Altitude Area Defense (Thaad) system because North Korea continues to develop ballistic missiles and make progress in miniaturizing nuclear warheads to go with them. South Korea and the U.S. currently deploy Patriot batteries to shoot down missiles as they approach their target. Thaad will offer another layer of defense.
