Summary of Just War Doctrine

Definitions

War – an armed conflict between sovereign States undertaken by public sanction  [Today this would have to include non-state entities waging war.]

Just War – defensive war

• as a response to unjust attack  
• as the only means of maintaining existence or rights or defending them

Unjust War – offensive war; punitive, self-aggrandizement etc.

Conditions that must be met for War to be Just

1. declared by the State itself

2. necessary in the last resort after diplomacy has failed

3. there must be a grave and just reason for it

4. the method of it must be just and in accordance with international law

5. an upright purpose must be intended

6. it may not be protracted after due satisfaction has been given or offered

7. the conditions of peace must be just, not severe, unless such severity is necessary for present self-defense

In cases of doubt

• When the justice of the war is not certainly just (i.e. just, with a moral certainty), the predominant opinion of theologians is that war may not be undertaken to redeem rights.

- this is consistent with the general moral principle that one may not act on a doubtful conscience, but must have moral certainty of the rightness of a proposed action.

• When the state is on the defensive (in the two ways noted above), it is sufficient that its own injustice (in the response) is not obvious. [ i.e. Its defensive war should be judged just until it is evidently not so.]

Duties of Soldiers

• Volunteers who join before a war begins, and conscripts, may usually assume their country is in the right.

• Volunteers after the war begins must satisfy themselves that the war is just.

• If the war is doubtfully just, soldiers must still obey (i.e. give the presumption to lawful authority)

• If the war is manifestly unjust (i.e. without any uncertainty), soldiers may not inflict harm on the enemy, though they may defend their own lives if attacked.

• Soldiers in a just cause must prosecute the war in accordance with the moral law and international treaty

Conduct of the War and the Peace

• The natural law and justice always apply, even in war.

• International treaties may go beyond the natural law and justice (e.g. prohibition of certain weapons) and must be followed by the parties who signed them.

- since treaties are contracts, if one side repudiates the treaty the other side ceases to be bound by it.

• Those not engaged in actual aggression nor under arms, nor in training, nor assisting aggression, may not be directly attacked (i.e. non-combatants).

• Prisoners of war who surrender and are accepted may not be killed or injured, excepted for serious crimes committed during captivity.

• Reasonable care must be taken that attacks on military targets (fortified towns, barracks, shelters for forces, munitions factories etc.) spare the lives and property of non-combatants.

- specifically, indiscriminate attacks intended to sap the morale of non-combatants are immoral.

• No means (e.g. explosive, bomb, NBC weapon) may be used if the consequences of its use is loss of civilian life out of all proportion to the destruction of legitimate military targets.

• Blockade and siege are just against military forces, even at the expense of civilians who happen to be in the same place.

• Reprisal taken as an act of revenge, or on the defenseless, is unjust.

• Victors may use all legitimate means to safeguard the peace, but may not utterly subjugate and break a people as a means to forestall mere future possible aggression. As much as possible within the demands of legitimate self-defense, the victors in a war must observe both justice and charity towards the defeated.

 Summarized from: Rev. Henry Davis, S.J., Moral and Pastoral Theology vol. 2 (NY: Sheed and Ward, 1935, 1959) 148-151.  

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