Digest of Biblical Civil Law

Even though siege warfare against walled cities became outdated with the use of gunpowder, there are principles of Deut. 20:19-20 that still apply.  The implication of the law against destroying fruit trees for siegework is that holy warfare is not destruction for destruction's sake.  There is an element of disinheritance in war, but it is always to be offset by an element of inheritance.  The principle means that crops, water sources and systems, livestock, beehives, and other sources of food and health are to be preserved during times of war.  The doctrines of total warfare and scorched earth run counter to God's law here.  Deaths of innocent civilians, collateral damage, and destruction of private property in general should be condemned.  Medical centers, pharmaceutical plants, factories and businesses, except those involved in hostilities, should be protected since they pertain directly to the sustenance of life for many people.  The passage says that the destruction of non-fruit trees is still allowed, which would allow defoliants in jungle warfare when necessary.
- Joel McDurmon, The Bible & War in America:  A Biblical view of an American obsession and steps to recover liberty, (Powder Springs, GA: American Vision, Inc., 2012), 15-18.