What history tells us to expect from Trump’s escalation in Los Angeles protests

A large body of research, spanning more than 50 years, shows that heavy-handed policing and militarized responses to civil unrest tend to make protests more volatile — not less.One of the earliest such findings came from the 1967 Kerner Commission, which investigated the causes of urban riots across the country. The commission found that in half the riots studied, aggressive police action, such as mass arrests or tear gas, had served as the catalyst for violence.