Although the rapid escalation of violence in Hong Kong seems terrifying enough, things may be about to get much worse. The communique of the recently concluded fourth plenum of the 19th Central Committee of the Chinese Communist Party (CCP) indicates that Chinese President Xi Jinping is planning to tighten his grip on the former British colony at any cost. He should prepare to rack up a formidable bill.

The communique includes two ominous pledges. First, China's central government will "control and rule" (guanzhi) Hong Kong (and Macau) using "all the powers vested in [it] under the constitution and the Basic Law," the mini-constitution that defines Hong Kong's status. Second, it will "build and improve a legal system and enforcement mechanism to defend national security" in both special administrative regions.

A few days after the plenum, the CCP's plan to assert its control over Hong Kong became clearer when it released the full text of the resolution endorsed there by its Central Committee. China's central government intends to change the process for appointing Hong Kong's chief executive and key officials reform the system governing how the Chinese National People's Congress Standing Committee interprets the Basic Law.