Typically the police are reactive and that's because the system is setup that way. Usually you can't arrest someone until he/she commits a crime (unless you stop them before and get them on conspiracy charges). However, with the shooting in Santa Fe, police could not have done anything to prevent it. If you want to blame the parents for not doing a better job ensuring their son didn't have access to their weapons, I'm with you on that. But saying the police didn't do enough to stop it is ridiculous. They can't monitor and chaperone every student at every school. Somewhere along the way, parental responsibility comes into play.