I'm asked this question a lot. Yes, most dogs can be taught to protect their handlers. The problem with this is we're actually building a loaded gun. Then handlers need to always control this drive. Accidental targeting can be devastating, morally & liability-speaking.
Therefore, I profess that if you already have a protective breed, leave it alone. Naturally your dog will protect you and your family as you build the healthy relationship of Leader & follower. By showing your dog calm & assertive leadership traits, trust will build along with his confidence. A sound, centered canine will protect his pack. It makes more sense to work with your dog in becoming the follower he should be while you strive to be the Leader he needs.