Just War Theory

Just War: Origins and Development

Jus ad bellum (law on going to war) and jus in bello (law in war, which will not be explored in depth here) emerged as formal concepts in the 4th and 5th centuries with St. Augustine of Hippo's refutation of charges that [Page 396]Christianity had undermined the Roman polity. The Christian message, he argued, is peace, but those who willfully attack the peace—heretics and pagans—legitimately could be opposed by force wielded in God's name. As Augustine wrote in The City of God, “For it is the wickedness of the opposing group which compels the wise man to wage just wars.”

Augustine proposed four justifications for “legitimate” wars: self-defense, to reclaim property, recover debt, and punish. Augustine also held that Christians had a divinely given duty to prevent the triumph of evil in this life, thus removing barriers to Christians becoming professional soldiers.

By the late 17th century, a consensus had emerged among Western theologians and authors of treatises on international law that seven jus ad bellum criteria must be met for a conflict to be “just”:

• just cause (correct a grave public evil or selfdefense)
• legitimate authority (only governments can declare war)
• right intention (secure a just and comprehensive peace for all belligerents)
• probability of success (overcoming the evil prompting war)
• proportionality (amount of force and weaponry limited to that needed to win)
• last resort (first exhaust all other means—diplomatic, economic, social)
• the evil and suffering from war must be less than the evil eliminated

The several humanitarian considerations restricting armed conflict (jus in bello) coalesced only in the mid-20th century:

• proportionality (as above)
• noncombatant immunity (only armed forces or other government agents participating in hostilities are legitimate targets)
• humane treatment of prisoners of war and medical and religious personnel
• prohibitions against using certain conventional weapons such as land mines and napalm
• safe conduct for those under white truce flags
• no targeting of undefended cultural, religious, or dangerous sites (e.g., nuclear power plants)

Evaluating U.S. Wars

Clearly, these principles attempt to regulate the occasions for going to war as well as the activities of combatants in war. But does history sustain traditional schoolbook claims that America only fights just wars? The record is mixed.

European colonists, bent on acquiring land, quickly came to blows with Native Americans, virtually annihilating entire peoples such as the Pequots and Narragansett in New England and the Algonquian confederacy in Virginia. Sometimes, especially when responding to attacks on settlements, the Europeans’ actions were clearly excessive. Pastor John Robinson acknowledged this in reproving the Plymouth colony's militia: “Necessity … of killing so many (and many more, it seems, they would if they could) I see not” (Buffington). Rhode Island's Roger Williams noted the recurring tendency to claim war as “defensive.” William Williams cautioned the Bay colony's leaders in a 1737 sermon (“Martial Wisdom Recommended”) that Christians should fight “only in a just cause. Not to gratify pride, Avarice and Ambition, to increase or enlarge our Possessions by the ruins of those who might dwell securely by us” (Buffington).

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