China is modernizing its military forces faster than anyone expected, escalating the potential danger to the island of Taiwan, to American forces and bases in Asia, and to the overall balance of power in the region. "China adheres to the military strategy of active defense and works to speed up the revolution of military affairs (RMA) with Chinese characteristics," says the white paper Beijing issued in December. It points to "leapfrog development" in high-tech weapons for its missile units, navy, and air force. Where many American and Asian analysts said before that China would be able to mount a credible...