“The direct costs of violent protests are fairly self-evident. People who may not have anything to do with the underlying grievances get injured or killed, their livelihoods are impaired, the communities in which the rioting takes place suffer property damage that can linger for decades, and the inevitable police response creates new dangers for innocent bystanders.”

https://nymag.com/intelligencer/2015/05/new-study-shows-riots-make-america-conservative.html