(1) the cause must be just,

(2) a right authority must make the decision to go to war,

(3) groups going to war must do so with a right intention,

(4) war must be undertaken only as a last resort,

(5) the goal of the war must be a likely emergent peace, and

(6) the war must be proportionate, that is, the total evil of a just war cannot outweigh the good achieved by the war