Answer:
Response of the authorities
Step-by-step explanation:
A peaceful protests other social movement actions can turn violent even when they are intentionally planned to be nonviolent because of the response of the authorities.
If a government want to use a coercive measure or ways to stop the protest either by using the military personnel to force people to quit the protest,violent might erupt which wasn't planned to be by the protesters.
Charles Tilly who lived from the year 1929-2008 was one of the greatest sociologist within the twentieth century