S ince Friday, China's People's Liberation Army Air Force has sent nearly 150 aircraft into Taiwan's air defense identification zone. Access to such a zone requires aircrews to request entry and to identify themselves and their course. Insisting that Taiwan is a breakaway province with no sovereign rights, China has ignored these requirements. But what's really going on? Well, these intrusions reflect Beijing's desire to deter Taipei from its cultivation of Western support. But the flights are also motivated by Xi Jinping's interest in projecting leadership strength. The Chinese army's display is certainly noteworthy in its scale and form. While...