Numerous people have criticized homeowners for having a gun in their hand or on their person when answering a door. I have always maintained that it is only prudent to do so. Home security systems can be very useful, of course. A standoff barrier, such as my old friend, Tex Ferguson, the highly decorated combat vet and intelligence operative used, works very well, as do surveillance cameras. Not everyone has such a system in place, or working, all the time. In any case, surveillance and standoff systems work best when backed up by armed force. I have reported numerous...