As was previously noted, historians trace the concept back to Augustine. Thomas Aquinas defined the theory and established the criteria for a just war. And a look at the times suggests that the "just war" concept was politically expedient. There was a threat from the Goths (Augustine) and the Ottoman Turks (Aquinas). In addition, in Aquinas' time there were the Christian Crusades and any recruitment effort was well worth establishing the doctrine in their minds.
And in finding and fighting a common foe rather than each other, the doctrine led to the ability of rulers to protect Martin Luther and other reformers. You could say "just war" helped Luther survive and his reformation efforts flourish!
No doubt Paul's words to the Corinthians about not taking each other to court served as a basis (1 Corinthians 6). If Christians ought not fight each other in court, they ought not make war on each other.
In brief, let's review the principles, first from Thomas Aquinas:
First, the legitimate authority who has the duty of preserving the common good must declare the war.
Secondly, a just cause for war must exist. St. Augustine, quoted by St. Thomas, said, "A just war is apt to be described as bone that avenges wrongs, when a nation or state has to be punished, for defusing to mace amends for the wrongs inflected by its subjects, or to reborn what it has seized unjustly.
Finally, St. Thomas said the warring party must have the right intention, "so that they intend the advancement of good or the avoidance of evil." St. Augustine noted, "True religion looks upon as peaceful those wars that are waged not for motives of aggrandizement or cruelty, but with the object of securing peace or punishing evil-doers, and of uplifting the good." An evil intention, such as to destroy a race or to absorb another nation, can turn a legitimately declared war waged for just cause into a wrongful act."
[fort.jpg]Today the concept is enlarged to the following eight points:
+ War must be the last resort after all other possible solutions have been tried and failed.
+ The reason for the war must be to redress rights actually violated or to defend against unjust demands backed by force.
+ The war must be openly and legally declared by a lawful government.
