Why the purge? China's Xi sidelines top military brass

The official line these days out of China is that it's a stable partner "in an uncertain world." So what to make of the bombshell news out of Beijing? Xi Jinping has purged his top general Zhang Youxia, with accusations against the 75-year-old loyalist that range from corruption to leaking nuclear secrets to the US. We ask about the reasons and the timing, what with the move fuelling speculation that an invasion of Taiwan could now come sooner rather than later.