A thorough reading of history shows that violent uprisings are de facto _what_ is effective, and certainly in post-industrial modern times. Empires cede control of territory when they become too expensive to maintain. Usually, that is in terms of violence, which threatens mercantile stability and integrability.

Unfortunately, the violence and instability that often accompanies secession doesn't always end up resulting in prosperity after independence. That is because violent or not, uprisings do not necessarily upset the power balance between the colonizer and the colonized. Some say the alphabet agencies that form the worldwide practice of SIGINT operate on this inertia -- well, I don't want to speculate about what I don't know about, but I think that at least my own country's declassified documents are telling. The USA has had a hand in kingmaking much of LatAm and the Middle East. Historically, I think this kind of proxying only ends when the empire itself shrivels.