If you want to understand what China’s Communist Party, wannabe boss-of-the-world, envisions for us all — just look today to the grim transformation of Hong Kong’s Victoria Park. This pleasant area near the harbor, with its greenery, sports pitches and big central lawn, is where, for more than 30 years, Hong Kongers have gathered and lit candles to celebrate the courage and dreams of liberty that animated China’s 1989 Tiananmen uprising, and mourn the slaughter with which China’s communists crushed that movement for freedom, centered in the heart of Beijing. Since 1989, Beijing’s commissars have gone all out inside mainland...