Getting hit in the head with a rock can cause a very, very serious injury. When the pendulum swings back after this January, I expect the police to fight back under conditions like this and “explain” to these punks that violence is not acceptable. When enough of them have a good “explaining to”...the violence will end.
Local police are under local control. Not much a president Trump can do about rioting Mexicans short of calling up federal forces to “encourage” the Mexicans to go back to Mexico.