An example of a holy war in the Old testament is The Crusades (1095-1291). Fought to capture control of the Holy-Land
Just cause - the war must have a just cause such as defending a country from an unprovoked attack
Proper authority - the war must be declared by the government of a country
Just intention - the war must have a good intention such as to bring about peace and get rid of a tyrant
Last resort - all other methods should be tried first
Win possible - it must have a reasonable chance of being successful and bringing about peace, it shouldn't be started if theirs no chance of winning
Proportionality - the war should be fought by just means. Force used should be in proportion to the other side, it shouldn't kill too many people
Balance of good - the good achieved by the war must outweigh the evil before it
Conscientious objectors are people who refused to fight in WW1 and WW2 and faced punishment as a result
Pax Christi is a global Catholic peace movement. It is grounded in the belief that peace is possible and that vicious cycle of violence and injustice can be broken