[2.6.8] St Augustine’s Just War Theory

St Agustine (354-430 AD) in the City of God (De Civitate Dei) and other works proposes a theory of how to initiate and conduct a just war. He thinks that:

  • Because of the pride, vanity, and fallen nature of man, wars between political states (see [2.6.7]), sects, religions are present in the world.
  • Wars have a coercive role in God’s plan for humanity.
  • Killing in wars is permissible even for Christian soldiers – as agents of the law, if the killing avoids a greater evil.
  • Christians involved in wars should decide and conduct wars in a just way.

In the UML Activity Diagram below, I propose a representation of the “business” process of decision-making and conducting a just war. The actions marked with yellow and cyan are St Augustine’s criteria.

Augustine’s just war theory
DECISION ABOUT JUST WAR Check if there is a just cause for war: “such as to defend the state from external invasion; to defend the safety or honor of the state, with the realization that their simultaneous defense might be impossible; to avenge injuries; to punish a nation for failure to take corrective action for wrongs (legal or moral) committed by its citizens; to come to the defense of allies; to gain the return of something that was wrongfully taken; or to obey a divine command to go to war (which, in practice, issues from the political head of state acting as God’s lieutenant on earth); and in any case, the just cause must be at least more just than the cause of one’s enemies”.

Check if there is a rightly intended will for war: “which has the restoration of peace as its prime objective, takes no delight in the wickedness of potential adversaries, views waging war as a stern necessity, tolerates no action calculated to provoke a war, and does not seek to conquer others merely for conquest’s sake or for territorial expansion”.

Check if the war is declared by a competnet authority

Check if the war is the last resort in order to achieve the objective of the just cause.
Declare war Declare war by a competent authority
CONDUCT JUST WAR Plan military action

Check if the military action is proportional to “the wrong to be avenged, with violence being constrained within the limits of military necessity”

Check if the military action discriminates between objects of violence (that is, combatants) and noncombatants, such as women, children, the elderly, the clergy”

Check if the military action observes good faith in its interactions with the enemy, by scrupulously observing treaties and not prosecuting the war in a treacherous manner.”

Conduct military action

Check if war’s objective is reached


First published: 30/1/2020

[2.6.7] St Augustine on Two (Plus One) Cities

St Agustine’s (354-430 AD) City of God (De civitate dei) is not a political treatise, however elaborates on some political issues. Here he describes the human community with a methaphor of two cities, which co-exist in the earthly realm, the city of God and the earthly city:

  • The city of God is the eternal community of humans with true love (caritas, love of God). This is not to be equated with the institutional church.
  • The earthly city is the temporary community of the humans with wrong love (cupidity)
  • The two cities co-exist and are intermingled in the frame of the political state, which is a punishment for the fallen man, but also has the role in upholding relative justice.

The OntoUML diagram below presents the main components of Augustine’s view on the earthly city, the city of God and the political state:

Augustine on two (plus one) cities
EarthlyCity The earthly city is a metaphor for the community of the persons with the wrong kind of love (love of self, of power, etc.). This community is temporary.is part of the PoliticalState
CityOfGodThe city of God is a metaphor for the community of the persons with the right love (love of God). This community is eternal.is part of the PoliticalState
PoliticalStateBecause the citizens of the earthly city and of the city of God live intermingled, the two cities are also intermingled, and are the two parts of the political state, which “is a divinely ordained punishment for fallen man, with its armies, its power to command, coerce, punish, and even put to death, as well as its institutions such as slavery and private property. God shapes the ultimate ends of man’s existence through it.  The state simultaneously serves the divine purposes of chastening the wicked and refining the righteous.  Also simultaneously, the state constitutes a sort of remedy for the effects of the Fall, in that it serves to maintain such modicum of peace and order as it is possible for fallen man to enjoy in the present world.”
Justice Justice can be true or relative.
TrueJusticeTrue justice, according to Augustine, “is love serving God only, and therefore ruling well all else.”TrueJustice characterizes CityOfGod
RelativeJustice“No earthly [political] state can claim to possess true justice, but only some relative justice by which one state is more just than another.  Likewise, the legitimacy of any earthly political regime can be understood only in relative terms:  The emperor and the pirate have equally legitimate domains if they are equally just.” (Mattox)RelativeJustice characterizes EarthlyCity
PersonA human person living its earthly or eternal life, who “was brought into existence to endure eternally. Damnation is the just desert of all men because of the Fall of Adam, who, having been created with free will, chose to disrupt the perfectly good order established by God. As the result of Adam’s Fall, all human beings are heirs to the effects of Adam’s original sin, and all are vessels of pride, avarice, greed and self-interest.” (Mattox)
CitizenOfEarthlyCityA Citizen of the Earthly City is characterized by: “wrong love. A person belongs to […] the earthly city or city of the devil if and only if he postpones love of God for self-love, proudly making himself his greatest good (De civitate dei 14.28). (Mendelson)is subkind of Person; member of the EarthlyCity
CitizenOfCityOfGod A Citizen of the City of God is characterized by: “right or […] love. A person belongs to the city of God if and only if he directs his love towards God even at the expense of self-love” (Mendelson). They are “pilgrims and foreigners”.is subkind of Person; member of the CityOfGod
Love Love is a crucial and overarching notion in Augustine’s ethics. It is closely related to virtue and often used synonymously with will […] or intention (intentio). […] love is a force in our souls that attracts us to the true beauty we find nowhere else but in and above ourselves; it drives us to ascend from the sensible to the intelligible world and to the cognition and contemplation of God […].” (Mendelson)
Caritas“love means the overall direction of our will (positively) toward God or (negatively) toward ourselves or corporeal creature (De civitate dei 14.7; […]). The former is called love in a good sense (caritas), the latter cupidity or concupiscence (cupiditas), i.e., misdirected and sinful love (De doctrina christiana 3.16).”(Mendelson) is Love; characterizes CitizenOfCityOfGod
Cupidity“love means the overall direction of our will (positively) toward God or (negatively) toward ourselves or corporeal creature (De civitate dei 14.7; […]). The former is called love in a good sense (caritas), the latter cupidity or concupiscence (cupiditas), i.e., misdirected and sinful love (De doctrina christiana 3.16).” (Mendelson)is Love; characterizes CitizenOfEarthlyCity


First published: 23/1/2020