When Gen. Wei Fenghe, China's defense minister, took to the stage at the Xiangshan security forum organized by the People's Liberation Army (PLA) in Beijing last month, he assured delegations from 64 countries that China's military "has always been a staunch defender of world peace."Yet in the same breath, he issued a sharp warning: "Taiwan is China's core interest," Wei said. "On these issues, it's extremely dangerous to challenge China's bottom line repeatedly.