Tennessee appears to have the concept of "Castle Doctrine" which says that "your home is your castle" and gives you a lot of latitude in what you can do to protect yourself and others but it doesn't extend to property. More the specific requirement is usually the belief that you (or they) are in immediate physical danger.
Attacking someone for stealing a flag from your property will probably land you in jail or worse.
Former Tn resident: yiu can shoot them if 1. They are in your house 2. They are threating your life, 3. You can ask them to get off your lawn 3 times then start blasting. I recall a deaf kid got shot for not getting off a lawn once and the guy was found not guilty.
Attacking someone for stealing a flag from your property will probably land you in jail or worse.
Ref: http://nashvilleattorneynow.com/criminal-defense/nashville-c...