Hong Kong’s security law: what it says, and why China is doing this now

Some answers to why Beijing imposed legislation on the city. "Hong Kong has become a key flashpoint in what some see as an emerging cold war between the U.S. and China. Exhibit A is Beijing’s decision to bypass Hong Kong’s legislature and impose new national-security legislation on the city to stamp out a yearlong protest movement." Joyu Wang explains what's happening in Hong Kong for The Wall Street Journal.