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.

Ref: http://nashvilleattorneynow.com/criminal-defense/nashville-c...