HONG KONG • How and why have Hong Kongers managed to keep going for months, and in such large numbers, waging wave after wave of protests to oppose encroachment from China, despite the vast differences among them?

One major point of contention concerns whether to resort to non-peaceful action and how close to skirt with violence. Take the occupation of the Hong Kong airport early last week. The sit-in, supposedly a peaceful initiative, devolved into clashes with the police and was marred after some protesters roughed up two mainlanders they suspected of being infiltrators sent by China. (One of the two turned out to be a reporter with the much-disdained Global Times, the hardline media face of the authorities in Beijing.) Amid fears that the movement's unity might unravel, some protesters then apologised, saying they had committed inappropriate acts in the heat of passion.