Erica Chenoweth initially thought that only violent protests were effective. However after analyzing 323 movements the results were opposite of what Erica thought:

For the next two years, Chenoweth and Stephan collected data on all violent and nonviolent campaigns from 1900 to 2006 that resulted in the overthrow of a government or in territorial liberation. They created a data set of 323 mass actions. Chenoweth analyzed nearly 160 variables related to success criteria, participant categories, state capacity, and more. The results turned her earlier paradigm on its head — in the aggregate, nonviolent civil resistance was far more effective in producing change.

If campaigns allow their repression to throw the movement into total disarray or they use it as a pretext to militarize their campaign, then they’re essentially co-signing what the regime wants — for the resisters to play on its own playing field. And they’re probably going to get totally crushed.