The Truth about Violence

Why can’t civilized people like ourselves simply rely on the police? Well, look around you: Do you see a cop? Unless you happen to be a police officer yourself, or are married to one, you are very unlikely to be attacked in the presence of law enforcement. The role of the police is to respond in the aftermath of a crime and, with a little luck, to catch the person who committed it. If you are ever targeted by a violent predator, whether you and your family are injured or killed will depend on what you do in the first moments of the encounter.? When it comes to survival, therefore, you are entirely on your own. Once you escape and are in a safe place, by all means call the police. But dialing 911 when an intruder has broken into your home is not a strategy for self-defense.[2] 

via The Blog : The Truth about Violence : Sam Harris.