In this world of missiles and other massive destruction arms, one may argue that there remains no need to train a common man for his self-defense, because it is virtually impossible for a man to combat against the possible destruction a missile brings.
But I would argue that such training can certainly decrease the losses of a community under attack. Also, two parties, possessing equally destructive weapons would want to avoid declaring wars on their borders, resulting in a battle that is entirely staged on roads and near civil localities, which we may term as terrorism.
Such circumstances put responsibility on the shoulders of civilians, because intrusion of army in civil localities may create more confusion and a sense of decreased civil liberty, further complicating the issue.
Hence, training residents of a locality so that they may help each other before, during or after an adversity can be of help.
Such training may start at school level, where basic rescue tactics, paramedical training, organized dispersal during an alarming situation may be demonstrated and explained. For this purpose Boys Scouts or Girls Guides sort of groups may be formed. Few volunteers, under the auspices of local police, may be trained in fighting if under attack by the terrorists (with proper records kept as to the identity of the volunteers being trained).
Such groups can not only help their fellow residents in a locality but can prove to be an aid to the police/rangers/army, so that they may divert their attention to more sensitive areas, leaving the less sensitive ones under the protection of the groups of civil self-defense.