A Just War

The prereading question that is asked is "does the War on Terror meet St. Thomas Aquinas' criteria for a just war?" Obviously it does not if you use his exact definition of a just war which includes the idea that the violence of the war must be proportional to the injury suffered to precipitate the war. Many more people have been killed during this war than in the attacks on September 11th. However is this determined by numbers alone? If 100 people die as a result of a terror attack and war is the last resort, but the war stop once 100 people are killed? Kind of unrealistic if you ask me.