Trained professionals may be against whom we have to defend ourselves. The military, while useful in time of war, it's use may be perverted and used against the people, ergo the right to keep and bear arms in necessary as a proper deterrent to this idea. Even the Japanese in WW II, would not invade us, as "there would be a gun behind every blade of grass." It is better to carry a gun for security, because carrying a policeman or soldier would be to heavy and just look silly. When you have seconds to live, police are just minutes away.