The question of non-violent tactics was canonically realized by the Buddhist movement in its original source form, during the Axial Age. The comments today give a hint of the sad outcome of that experiment.
The blog The Gurdjieff Con has most of the text of Prem Nath Bazaz’ history of the Gita, and early Buddhism in India. He tries to show how the Gita was written as propaganda to justify the violent extermination of the Buddhists, who were close to achieving a non-violent revolution to transform India. The endgame was their massacre and their desperate refuge in greater Asia and Tibet, as Buddhism died out in its land of origin. After that the buddhists had learened their lesson. Non-violence led to something very dark indeed.
The point here is to note the reality: powerful authorities leave non-violent groups alone, until they become a real threat. Then they will not receive a non-violent response. They may well be simply exterminated.
Non-violent tactics have many dimensions, but the sentimental misuse of them will discredit them, and there is always the danger of greater violence in the end. For a simple reason: non-violent protest turns activists into sitting ducks.