Last week marked the 20th anniversary of the Tiananmen Square demonstrations, which culminated with the Beijing massacre, in which hundreds, possibly thousands, of people were killed. In Hong Kong, the annual candlelight vigil in Victoria Park was attended by some 150,000 people, who listened to excerpts from the late party leader Zhao Ziyang's memoirs, a taped message from Ding Zilin, leader of the group known as Tiananmen Mothers, all o...