Basic Principles of Christian Just War
jus ad bellum
(1) The cause and intention of a war must be just. The war must have limited objections and objectives that are just in the eyes of God. This includes protecting the innocent who are threatened or restoring order in the society. Wars of conquest or wars to “spread democracy” are thus unjust.
(2) In a just war there must be a right to intervene with violence.
(3) There must be a declaration of war by lawful authorities.
(4) In a just war, war is the last resort. Even if a nation has a just cause and a right to intervene, it must not engage in warfare unless it is the last resort. An appeal must first be made to right before recourse is made to might.
(5) A war is just only if it is entered into with a probability of success. Not all just causes can be successfully prosecuted. It is unjust to ask for vain sacrifice.
jus in bello
(6) A just war is one where the cost that is to be incurred is not thought to be a greater evil than that which is to be remedied.
(7) The means of a just war must be both discriminative and proportional. Total war is unbiblical. A just war is one which carefully distinguishes civilians from combatants. Wars should not be needlessly destructive. The violence used must only be sufficient to restore the peace that has been destroyed by the aggressor nation.
Advocates of Just War Theory
Augustine is the “father” of just war theory, but his thoughts on the subject are dispersed throughout his vast corpus. Aquinas systematized them in the ST. The pertinent section is found here.
The Westminster Standards demand JWT, although it does not articulate the details (see WCF 23:2 and WLC Q. 136). Almost all Reformed theologians have advocated JWT, which invariably amounts to defensive war. If there are exceptions, I am ignorant of them.
Calvin: Institutes, book 4, sections 11 and 12.
Turretin: Institutes, Topic 11, Question 17.
Dabney: Lectures in Systematic Theology, Lecture 33, Question 7.
Charles Hodge: Systematic Theology, Part 3, Chapter 19, Section 10.
John Murray: Principles of Conduct, pp. 178-9.
Greg Bahnsen did a nice series on JWT called “A Christian View of War,” available from Covenant Media Foundation.
Originally posted at First Word
