In some ways, one could see it as a ridiculous idea. That systems created and supported by violence could be threatened by peaceful protest.
Time and again over history however that is what we have seen. Indeed non-violent movements are often more successful than violent ones. Violence plays the game using the oppressor's own rules, however, when they lose the moral authority to govern in society their days are often numbered.
For anyone who wants to understand how society can change or be changed, they lay out in detail the tactics used by the people leading change. We can learn lessons from the past, how carefully they thought through what they were doing, and the philosophies and people that inspired them. Nonviolence is a tool open to those without power, but it is also a tool which best sets up a society for what happens after the revolution is successful.
If you want to learn more about this remarkable reality, then this book details a number of famous instances. The First Russian Revolution, Indian Self Rule, Solidarity, Civil Rights, Apartheid and more. These are parts of history I think it is important for us all to learn from.
This book is a companion to the documentary series of the same name, which I also highly recommend.