Editing Just war theory (section)

==Origins==
===Ancient Egypt===
A 2017 study found that the just war tradition can be traced as far back as to [[Ancient Egypt]].<ref name="cox">{{Cite journal|last=Cox|first=Rory|title=Expanding the History of the Just War: The Ethics of War in Ancient Egypt|journal=International Studies Quarterly|volume=61|issue=2|page=371|doi=10.1093/isq/sqx009|year=2017|hdl=10023/17848|hdl-access=free}}</ref> Egyptian ethics of war usually centered on three main ideas, these including the cosmological role of Egypt, the pharaoh as a divine office and executor of the will of the gods, and the superiority of the Egyptian state and population over all other states and peoples. Egyptian political theology held that the pharaoh had the exclusive legitimacy in justly initiating a war, usually claimed to carry out the will of the gods. [[Senusret I]], in the [[Twelfth Dynasty]], claimed, "I was nursed to be a conqueror...his [Atum's] son and his protector, he gave me to conquer what he conquered." Later pharaohs also considered their sonship of the god Amun-Re as granting them absolute ability to declare war on the deity's behalf. Pharaohs often visited temples prior to initiating campaigns, where the pharaoh was believed to receive their commands of war from the deities. For example, [[Kamose]] claimed that "I went north because I was strong (enough) to attack the Asiatics through the command of Amon, the just of counsels." A [[stele]] erected by [[Thutmose III]] at the Temple of Amun at [[Karnak]] "provides an unequivocal statement of the pharaoh's divine mandate to wage war on his enemies." As the period of the [[New Kingdom of Egypt|New Kingdom]] progressed and Egypt heightened its territorial ambition, so did the invocation of just war aid the justification of these efforts. The universal principle of [[Maat]], signifying order and justice, was central to the Egyptian notion of just war and its ability to guarantee Egypt virtually no limits on what it could take, do, or use to guarantee the ambitions of the state.<ref name="cox" />

===India===
The Indian [[Hinduism|Hindu]] [[Indian epic poetry|epic]], the ''[[Mahabharata]]'', offers the first written discussions of a "just war" (''[[dharma-yuddha]]'' or "righteous war"). In it, one of five ruling brothers (''[[Pandava]]s'') asks if the suffering caused by war can ever be justified. A long discussion then ensues between the siblings, establishing criteria like ''proportionality'' ([[Ratha|chariots]] cannot attack cavalry, only other chariots; no attacking people in distress), ''just means'' (no poisoned or barbed arrows), ''just cause'' (no attacking out of rage), and fair treatment of captives and the wounded.<ref>{{cite book |author1=Paul Robinson |title=Just War in Comparative Perspective |year=2017 |isbn=9781351924528 |page=|publisher=Routledge }}</ref>

In [[Sikhism]], the term ''[[Dharamyudh (Sikhism)|dharamyudh]]'' describes a war that is fought for just, righteous or religious reasons, especially in defence of one's own beliefs. Though some core tenets in the Sikh religion are understood to emphasise peace and nonviolence, especially before the 1606 execution of [[Guru Arjan]] by [[Mughal Empire|Mughal]] Emperor [[Jahangir]],<ref name="Syan">{{Cite book |last=Syan |first=Hardip Singh |url=https://books.google.com/books?id=9RzzxcEL4C0C&pg=PA3 |title=Sikh Militancy in the Seventeenth Century: Religious Violence in Mughal and Early Modern India |date=2013 |publisher=I.B.Tauris |isbn=9781780762500 |location=London & New York |pages=3–4, 252 |access-date=15 September 2019}}</ref> military force may be justified if all peaceful means to settle a conflict have been exhausted, thus resulting in a ''dharamyudh''.<ref name="Fenech">{{Cite book |author1=Louis E. Fenech |title=Historical Dictionary of Sikhism |author2=W. H. McLeod |date=2014 |publisher=Rowman & Littlefield |isbn=9781442236011 |pages=99–100}}</ref>

===East Asian===
[[Chinese philosophy]] produced a massive body of work on warfare, much of it during the [[Zhou dynasty]], especially the [[Warring States era]]. War was justified only as a last resort and only by the rightful sovereign; however, questioning the decision of the emperor concerning the necessity of a military action was not permissible. The success of a military campaign was sufficient proof that the campaign had been righteous.<ref>{{Cite journal | url=https://irstudies.org/index.php/jirs/article/view/777/753| title= A Confucian Contribution to the Catholic Just War Tradition| journal=Journal of Interreligious Studies | date=2023 | author= Kwon, David}}</ref>

Japan did not develop its own doctrine of just war but between the 5th and the 7th centuries drew heavily from Chinese philosophy, and especially [[Confucianism|Confucian]] views. As part of the Japanese campaign to take the northeastern island [[Honshu]], Japanese military action was portrayed as an effort to "pacify" the [[Emishi]] people, who were likened to "bandits" and "wild-hearted wolf cubs" and accused of invading Japan's frontier lands.<ref name="routledge2004">{{cite book |last=Friday |first=Karl F. |author1-link=Karl Friday |url=https://books.google.com/books?id=DROBAV-DQ9IC&pg=PA20 |title=Samurai, Warfare and the State in Early Medieval Japan |date=2004 |publisher=Routledge |isbn=9781134330225 |pages=21–22}}</ref>

===Ancient Greece and Rome===
The notion of just war in Europe originates and is developed first in [[ancient Greece]] and then in the [[Roman Empire]].<ref>Gregory Raymond, ''The Greco-Roman Roots of the Western Just War Tradition'', Routledge 2010.</ref><ref>Rory Cox, "The Ethics of War up to Thomas Aquinas" in (eds. Lazar & Frowe) ''The Oxford Handbook of Ethics of War'', Oxford 2018.</ref><ref>Cian O'Driscoll, "Rewriting the Just War Tradition: Just War in Classical Greek Political Thought and Practice," International Studies Quarterly (2015).</ref>

It was [[Aristotle]] who first introduced the concept and terminology to the [[Hellenic world]] that called war a last resort requiring conduct that would allow the restoration of peace. Aristotle argues that the cultivation of a military is necessary and good for the purpose of self-defense, not for conquering: "The proper object of practising military training is not in order that men may enslave those who do not deserve slavery, but in order that first they may themselves avoid becoming enslaved to others" ([[Politics (Aristotle)|Politics]], Book 7).<ref>{{cite web |last1=Aristotle |title=Politics, Book 7 |url=http://www.perseus.tufts.edu/hopper/text?doc=Perseus:abo:tlg,0086,035:7 |website=Perseus Digital Library}}</ref>

[[Stoicism|Stoic]] philosopher [[Panaetius]] considered war inhuman, but he contemplated just war when it was impossible to bring peace and justice by peaceful means. Just war could be waged solely for retribution or defense, in both cases having to be declared officially. He also established the importance of treating the defeated in a civilized way, especially those who surrendered, even after a prolonged conflict.<ref>{{cite book|last=Capelle|first=Wilhelm|title=History of Greek philosophy|date=2020|publisher=De Gruyter|isbn=9783112318744|page=358}}</ref>

In [[ancient Rome]], a "just cause" for war might include the necessity of repelling an invasion, or retaliation for pillaging or a breach of treaty.<ref>Livy 9.1.10; [[Cicero]], ''[[Divinatio in Caecilium]]'' 63; ''De provinciis consularibus'' 4; ''Ad Atticum'' VII 14, 3; IX 19, 1; ''Pro rege Deiotauro'' 13; ''[[De officiis]]'' I 36; ''Philippicae'' XI 37; XIII 35; ''De re publica'' II 31; III 35; [[Isidore of Seville]], ''Origines'' XVIII 1, 2; [[Modestinus]], ''Libro I regolarum'' = ''[[Corpus Juris Civilis|Digesta]]'' I 3, 40; [[E. Badian]], ''Roman Imperialism in the Late Republic'' (Ithaca 1968, 2nd ed.), p.11.</ref> War was always potentially ''[[nefas]]'' ("wrong, forbidden"), and risked [[Religion in ancient Rome|religious pollution and divine disfavor]].<ref>[[William Warde Fowler]], ''The Roman Festivals of the Period of the Republic'' (London 1925), pp. 33ff.; M. Kaser, ''Das altroemische Ius'' (Goettingen 1949), pp. 22ff; P. Catalano, ''Linee del sistema sovrannazionale romano'' (Torino 1965), pp. 14ff.; W. V. Harris, ''War and imperialism in Republican Rome, 327-70 B.C.'' (Oxford 1979), pp. 161 ff.</ref> A "just war" (''bellum iustum'') thus required a ritualized [[declaration of war|declaration]] by the [[fetial]] priests.<ref>[[Livy]] 1.32; 31.8.3; 36.3.9</ref> More broadly, conventions of war and treaty-making were part of the ''[[ius gentium]]'', the "law of nations", the customary moral obligations regarded as innate and universal to human beings.<ref>Cicero, ''De officiis'' 3.17.69; [[Marcia L. Colish]], ''The Stoic Tradition from Antiquity to the Early Middle Ages'' (Brill, 1980), p. 150.</ref>

===Christian views===
Christian theory of the Just War begins around the time of [[Augustine of Hippo]] (Saint Augustine).<ref>[http://olympia.anglican.org/churches/B/stdunstan/Beliefs/Christians_War/Christians_War_2.htm Christians and War: Augustine of Hippo and the "Just War theory"] {{webarchive |url=https://web.archive.org/web/20061128152303/http://olympia.anglican.org/churches/B/stdunstan/Beliefs/Christians_War/Christians_War_2.htm |date=28 November 2006 }}</ref> The Just War theory, with some amendments, is still used by Christians today as a guide to whether or not a war can be justified. Christians may argue "Sometimes war may be necessary and right, even though it may not be good." In the case of a country that has been invaded by an occupying force, war may be the only way to restore justice.&nbsp;<ref>{{cite web |date=27 September 2024 |title=Forgiveness What is a Just War? |url=https://www.bbc.co.uk/bitesize/guides/z2b36yc/revision/4 |url-status=dead |archive-url=https://web.archive.org/web/20230313051346/https://www.bbc.co.uk/bitesize/guides/z2b36yc/revision/4 |archive-date=13 March 2023 |access-date=11 May 2020 |website=Bitesize |publisher=[[BBC]] }}</ref>

====Saint Augustine====
[[Saint Augustine]] held that individuals should not resort immediately to violence, but God has given the sword to government for a good reason (based upon Romans 13:4). In ''Contra Faustum Manichaeum'' book 22 sections 69–76, Augustine argues that Christians, as part of a government, need not be ashamed of protecting peace and punishing wickedness when they are forced to do so by a government. Augustine asserted that was a personal and philosophical stance: "What is here required is not a bodily action, but an inward disposition. The sacred seat of virtue is the heart."<ref>{{cite web|url=http://www.christianitytoday.com/ct/2001/septemberweb-only/9-17-55.0.html|title=A Time For War?|author=Robert L. Holmes|work=ChristianityToday.com|date=September 2001 |access-date=25 April 2015}}</ref>

Nonetheless, he asserted, peacefulness in the face of a grave wrong that could be stopped by only violence would be a sin. Defense of oneself or others could be a necessity, especially when it is authorized by a legitimate authority:<blockquote>They who have waged war in obedience to the divine command, or in conformity with His laws, have represented in their persons the public justice or the wisdom of government, and in this capacity have put to death wicked men; such persons have by no means violated the commandment, "Thou shalt not kill."<ref name=":0b">{{cite web|url=http://etext.lib.virginia.edu/etcbin/toccer-new2?id=AugCity.xml&images=images/modeng&data=/texts/english/modeng/parsed&tag=public&part=all |archive-url=https://web.archive.org/web/20130725190746/http://etext.lib.virginia.edu/etcbin/toccer-new2?id=AugCity.xml&images=images%2Fmodeng&data=%2Ftexts%2Fenglish%2Fmodeng%2Fparsed&tag=public&part=all |title=City of God |archive-date=25 July 2013 |access-date=25 April 2015 |url-status=dead }}</ref></blockquote>While not breaking down the conditions necessary for war to be just, Augustine nonetheless originated the very phrase itself in his work [[City of God (book)|''The City of God'']]:

<blockquote>But, say they, the wise man will wage Just Wars. As if he would not all the rather lament the necessity of just wars, if he remembers that he is a man; for if they were not just he would not wage them, and would therefore be delivered from all wars.<ref name=":0b"/></blockquote>

Augustine further taught:
<blockquote>No war is undertaken by a good state except on behalf of good faith or for safety.<ref >City of God, 22.6, quoted in {{cite web |last1=Lockwood |first1=Thornton |title=Cicero's Philosophy of Just War |url=https://philarchive.org/archive/LOCCPO |website=PhilArchive |access-date=28 July 2023}} The text seems from a missing fragment of [[Cicero]]'s dialog [[On the Republic]], by the Laelius character.</ref></blockquote>

J. Mark Mattox writes,<blockquote>In terms of the traditional notion of jus ad bellum (justice of war, that is, the circumstances in which wars can be justly fought), war is a coping mechanism for righteous sovereigns who would ensure that their violent international encounters are minimal, a reflection of the [[Will of God|Divine Will]] to the greatest extent possible, and always justified. In terms of the traditional notion of jus in bello (justice in war, or the moral considerations which ought to constrain the use of violence in war), war is a coping mechanism for righteous combatants who, by divine edict, have no choice but to subject themselves to their political masters and seek to ensure that they execute their war-fighting duty as justly as possible.<ref name="augustine_war_and_peace_just_war">[http://www.iep.utm.edu/aug-poso/#SH3c Augustine: Political and Social Philosophy], §3-c "War and Peace – The Just War"</ref></blockquote>

====Isidore of Seville====
[[Isidore of Seville]] writes:
<blockquote>Those wars are unjust which are undertaken without cause. For aside from vengeance or to fight off enemies no just war can be waged. <ref >Etymologies 18.1.2–3, quoted in {{cite web |last1=Lockwood |first1=Thornton |title=Cicero's Philosophy of Just War |url=https://philarchive.org/archive/LOCCPO |website=PhilArchive |access-date=28 July 2023}}. The text seems from a missing fragment of [[Cicero]]'s dialog [[On the Republic]], by the Laelius character.</ref></blockquote>

====Peace and Truce of God====
{{Main|Peace and Truce of God}}
The medieval [[Peace_and_Truce_of_God#Peace_of_God|Peace of God]] (Latin: {{lang|la|pax dei}}) was a 10th century mass movement in Western Europe instigated by the clergy that granted immunity from violence for non-combatants.

Starting in the 11th Century, the [[Peace_and_Truce_of_God#Truce_of_God|Truce of God]] (Latin: {{lang|la|treuga dei}}) involved Church rules that successfully limited when and where fighting could occur: Catholic forces (e.g. of warring [[baron]]s) could not fight each other on Sundays, Thursdays, holidays, the entirety of [[Lent]] and [[Advent]] and other times, severely disrupting the conduct of wars. The 1179 [[Third Council of the Lateran]] adopted a version of it for the whole church.

====Saint Thomas Aquinas====
{{See|Thomas Aquinas#Just war}}
[[File:Saint Thomas Aquinas Reading.png|thumb|[[Thomas Aquinas|Saint Thomas Aquinas]] contributed to the development of the just war theory in medieval Europe. ]]
The just war theory by [[Thomas Aquinas]] has had a lasting impact on later generations of thinkers and was part of an emerging consensus in [[medieval Europe]] on just war.<ref name=":1">{{Cite book|title=Thomas Aquinas on War and Peace|author=Gregory M. Reichberg|publisher=Cambridge University Press|year=2017|isbn=9781107019904|page=viii}}</ref> In the 13th century Aquinas reflected in detail on peace and war. Aquinas was a [[Dominican friar]] and contemplated the teachings of the Bible on peace and war in combination with ideas from [[Aristotle]], [[Plato]], [[Socrates]], [[Saint Augustine]] and other philosophers whose writings are part of the [[Western canon]]. Aquinas' views on war drew heavily on the {{lang|la|[[Decretum Gratiani]]}}, a book the Italian monk Gratian had compiled with passages from the Bible. After its publication in the 12th century, the {{lang|la|Decretum Gratiani}} had been republished with commentary from [[Pope Innocent IV]] and the Dominican friar [[Raymond of Penafort]]. Other significant influences on Aquinas just war theory were [[Alexander of Hales]] and [[Henry of Segusio]].<ref>{{Cite book|title=Thomas Aquinas on War and Peace|author=Gregory M. Reichberg|publisher=Cambridge University Press|year=2017|isbn=9781107019904|page=vii}}</ref>

In ''[[Summa Theologica]]'' Aquinas asserted that it is not always a [[sin]] to wage war, and he set out criteria for a just war. According to Aquinas, three requirements must be met. Firstly, the war must be waged upon the command of a rightful [[sovereign]]. Secondly, the war needs to be waged for just cause, on account of some wrong the attacked have committed. Thirdly, warriors must have the right intent, namely to promote good and to avoid evil.<ref>{{Cite book |last=Aquinas |first=Thomas |url=https://ccel.org/ccel/aquinas/summa/summa |title=Summa Theologica |publisher=Christian Classics Ethereal Library |pages=pt. II, sec. 2, q. 40, a. 1}}</ref><ref>{{Cite book|title=The Oxford Handbook of Ethics of War |editor=Seth Lazar |editor2=Helen Frowe|publisher=Oxford University Press|year=2018|isbn=9780199943418|page=114}}</ref> Aquinas came to the conclusion that a just war could be offensive and that injustice should not be tolerated so as to avoid war. Nevertheless, Aquinas argued that violence must only be used as a last resort. On the [[battlefield]], violence was only justified to the extent it was necessary. Soldiers needed to avoid cruelty and a just war was limited by the conduct of just combatants. Aquinas argued that it was only in the pursuit of justice, that the good intention of a moral act could justify negative consequences, including the killing of the innocent during a war.<ref>{{Cite book|title=The Oxford Handbook of Ethics of War |editor=Seth Lazar |editor2=Helen Frowe|publisher=Oxford University Press|year=2018|isbn=9780199943418|page=115}}</ref>

====Renaissance and Christian Humanists====
Various [[Renaissance humanists]] promoted [[Pacificist]] views.

* [[John Colet]] famously preached a Lenten sermon before Henry VIII, who was preparing for a war, quoting Cicero "Better an unjust peace rather than the justest war."<ref>{{cite journal |last1=MacKenzie |first1=Kathleen |title=John Colet of Oxford |journal=Dalhousie Review |volume=21 |issue=1 |pages=15–28 |url=https://dalspace.library.dal.ca/bitstream/handle/10222/57562/dalrev_vol21_iss1_pp15_28.pdf?sequence=1&isAllowed=y |access-date=28 July 2023}}</ref>
* [[Erasmus of Rotterdam]] wrote numerous works on peace which criticized Just War theory as a smokescreen and added [[Erasmus#Pacifism|extra limitations]], notably ''The Complaint of Peace'' and the ''Treatise on War'' (Dulce bellum inexpertis).

A leading humanist writer after the Reformation was legal theorist [[Hugo Grotius]], whose [[Hugo_Grotius#De_Jure_Belli_ac_Pacis|''De jura belli ac pacis'']] re-considered Just War and fighting wars justly.

==== First World War ====
At the beginning of the [[First World War]], a group of theologians in Germany published a manifesto that sought to justify the actions of the German government. At the British government's request, [[Randall Davidson]], [[Archbishop of Canterbury]], took the lead in collaborating with a large number of other religious leaders, including some with whom he had differed in the past, to write a rebuttal of the Germans' contentions. Both German and British theologians based themselves on the just war theory, each group seeking to prove that it applied to the war waged by its own side.<ref>Mews, Stuart. "Davidson, Randall Thomas, Baron Davidson of Lambeth (1848–1930), Archbishop of Canterbury", [[Oxford Dictionary of National Biography]], [[Oxford University Press]], 2011.</ref>

====Contemporary Catholic doctrine====
The just war doctrine of the [[Catholic Church]] found in the 1992 ''[[Catechism of the Catholic Church]]'', in paragraph 2309, lists four strict conditions for "legitimate defense by military force:"<ref>{{cite book|title=Catechism of the Catholic Church|edition=2|publisher=Liberia Editrice Vaticana|isbn=1574551108|url=https://archive.org/details/catechismofcatho2000cath|access-date=25 April 2015|year=2000|url-access=registration}}</ref><ref>{{cite web|title=Just-War Theory, Catholic Morality, And The Response To International Terrorism.
|url=https://www.catholicculture.org/culture/library/view.cfm?id=4644|access-date=11 May 2020}}</ref>
* The damage inflicted by the aggressor on the nation or community of nations must be lasting, grave and certain.
* All other means of putting an end to it must have been shown to be impractical or ineffective.
* There must be serious prospects of success.
* The use of arms must not produce evils and disorders graver than the evil to be eliminated.

The ''[[Compendium of the Social Doctrine of the Church]]'' elaborates on the just war doctrine in paragraphs 500 to 501, while citing the [[Charter of the United Nations]]:<ref name="compendio">{{cite web|url=https://www.vatican.va/roman_curia/pontifical_councils/justpeace/documents/rc_pc_justpeace_doc_20060526_compendio-dott-soc_en.html|title=Compendium of the Social Doctrine of the Church|access-date=10 April 2024}}</ref>

{{quotation|If this responsibility justifies the possession of sufficient means to exercise this right to defense, States still have the obligation to do everything possible "to ensure that the conditions of peace exist, not only within their own territory but throughout the world". It is important to remember that "it is one thing to wage a war of self-defense; it is quite another to seek to impose domination on another nation. The possession of war potential does not justify the use of force for political or military objectives. Nor does the mere fact that war has unfortunately broken out mean that all is fair between the warring parties".

''The Charter of the United Nations ... is based on a generalized prohibition of a recourse to force to resolve disputes between States, with the exception of two cases: legitimate defence and measures taken by the Security Council within the area of its responsibilities for maintaining peace.'' In every case, exercising the right to self-defence must respect "the traditional limits of necessity and proportionality".

''Therefore, engaging in a preventive war without clear proof that an attack is imminent cannot fail to raise serious moral and juridical questions.'' International legitimacy for the use of armed force, on the basis of rigorous assessment and with well-founded motivations, can only be given by the decision of a competent body that identifies specific situations as threats to peace and authorizes an intrusion into the sphere of autonomy usually reserved to a State.||''[[Compendium of the Social Doctrine of the Church]]''<ref name="compendio"/>}}

Pope [[John Paul II]] in an address to a group of soldiers noted the following:<ref>{{Cite web|url=https://www.catholiceducation.org/en/culture/catholic-contributions/the-church-s-just-war-theory-part-1.html|title=The Church's Just War Theory|last=Saunders|first=William|website=Catholic Education Resource Center|date=19 October 2000 |language=en-US|access-date=10 May 2020}}</ref> {{Blockquote|Peace, as taught by Sacred Scripture and the experience of men itself, is more than just the absence of war. And the Christian is aware that on earth a human society that is completely and always peaceful is, unfortunately, an utopia and that the ideologies which present it as easily attainable only nourish vain hopes. The cause of peace will not go forward by denying the possibility and the obligation to defend it.}}

====Russian Orthodox Church====
The ''War and Peace'' section in the ''Basis of the Social Concept of the Russian Orthodox Church'' is crucial for understanding the [[Russian Orthodox Church]]'s attitude towards war. The document offers criteria of distinguishing between an aggressive war, which is unacceptable, and a justified war, attributing the highest moral and sacred value of military acts of bravery to a true believer who participates in a justified war. Additionally, the document considers the just war criteria as developed in Western Christianity to be eligible for Russian Orthodoxy; therefore, the justified war theory in Western theology is also applicable to the Russian Orthodox Church.<ref>{{cite journal|doi=10.3390/rel11010002|doi-access=free|title='Militant Piety in 21st-Century Orthodox Christianity: Return to Classical Traditions or Formation of a New Theology of War?|year=2019|last1=Knorre|first1=Boris|last2=Zygmont|first2=Aleksei|journal=Religions|volume=11|page=2}} [[File:CC-BY icon.svg|50px]] Text was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0 Creative Commons Attribution 4.0 International License].</ref>

In the same document, it is stated that wars have accompanied human history since the [[fall of man]], and according to [[the gospel]], they will continue to accompany it. While recognizing war as evil, the Russian Orthodox Church does not prohibit its members from participating in hostilities if there is the security of their neighbours and the restoration of trampled justice at stake. War is considered to be necessary but undesirable. It is also stated that the Russian Orthodox Church has had profound respect for soldiers who gave their lives to protect the life and security of their neighbours.<ref>{{cite web|url=https://old.mospat.ru/en/documents/social-concepts/viii|title=Social Concepts, Chapter VIII.|language=en-GB|access-date=2024-11-23}}</ref>

===Just war tradition===
The just war theory, propounded by the medieval Christian philosopher [[Thomas Aquinas]], was developed further by legal scholars in the context of [[international law]]. [[Cardinal Cajetan]], the jurist [[Francisco de Vitoria]], the two [[Jesuit priest]]s [[Luis de Molina]] and [[Francisco Suárez]], as well as the [[humanist]] [[Hugo Grotius]] and the lawyer [[Luigi Taparelli]] were most influential in the formation of a ''just war tradition''. The just war tradition, which was well established by the 19th century, found its practical application in the [[Hague Peace Conferences]] (1899 and 1907) and in the founding of the [[League of Nations]] in 1920. After the [[United States Congress]] declared war on Germany in 1917, Cardinal [[James Gibbons]] issued a letter that all Catholics were to support the war<ref name=NCR>{{cite news|title=Ben Salmon and the Army of Peace |url= http://ncronline.org/blogs/road-peace/ben-salmon-and-army-peace |newspaper=[[National Catholic Reporter]] |author= John Dear |date= 23 February 2010}}</ref> because "Our Lord Jesus Christ does not stand for peace at any price... If by Pacifism is meant the teaching that the use of force is never justifiable, then, however well meant, it is mistaken, and it is hurtful to the life of our country."<ref>{{cite book|title= A History of the Parish of Trinity Church in the City of New York: The rectorship of Dr. William Thomas Manning 1908 to 1921|author=C. T. Bridgeman |year=1962|page=256}}</ref>

Armed conflicts such as the [[Spanish Civil War]], [[World War II]] and the [[Cold War]] were, as a matter of course, judged according to the norms (as established in Aquinas' just war theory) by philosophers such as [[Jacques Maritain]], [[Elizabeth Anscombe]] and [[John Finnis]].<ref name=":1" />

The first work dedicated specifically to ''just war'' was the 15th-century sermon ''De bellis justis'' of [[Stanisław of Skarbimierz]] (1360–1431), who justified war by the [[Kingdom of Poland (1385–1569)|Kingdom of Poland]] against the [[Teutonic Knights]].<ref>{{Cite book |last=David |first=Saul |chapter-url= https://books.google.com/books?id=8Llw8JSZEXYC&dq=De+bellis+justis+Stanis%C5%82aw+of+Skarbimierz&pg=PA345 |title= The Encyclopedia of War from Ancient Egypt to Iraq |date=1 October 2009 |publisher=Dorling Kindersley Limited |isbn= 978-1-4053-4778-5 |pages= 345 |language= en |chapter= Ethics of War |author-link= Saul David}}</ref> [[Francisco de Vitoria]] criticized the conquest of America by the [[History of Spain|Spanish]] [[conquistador]]s on the basis of just-war theory.<ref>{{Cite journal| url= https://lawreview.avemarialaw.edu/wp-content/uploads/2019/06/AMLR.v.10i2.salas_.pdf| title= Francisco de Vitoria on the Ius Gentium and the American Indios| journal= Ave Maria Law Review| date= 2012| author= Victor M. Salas Jr.| access-date= 11 July 2022| archive-date= 9 December 2021| archive-url= https://web.archive.org/web/20211209150822/https://lawreview.avemarialaw.edu/wp-content/uploads/2019/06/AMLR.v.10i2.salas_.pdf| url-status= dead}}</ref> With [[Alberico Gentili]] and [[Hugo Grotius]], just war theory was replaced by [[international law]] theory, codified as a set of rules, which today still encompass the points commonly debated, with some modifications.<ref>[[Gutman]] R, Rieff D. ''[[Crimes of War]]: What the Public Should Know''. New York, NY: [[W. W. Norton & Company]]; 1999</ref>

Just-war theorists combine a moral abhorrence towards war with a readiness to accept that war may sometimes be necessary. The criteria of the just-war tradition act as an aid in determining whether resorting to arms is morally permissible. Just-war theories aim "to distinguish between justifiable and unjustifiable uses of organized armed forces"; they attempt "to conceive of how the use of arms might be restrained, made more humane, and ultimately directed towards the aim of establishing lasting peace and justice".<ref>{{cite web |url=http://www.justwartheory.com |title=JustWarTheory.com |publisher=JustWarTheory.com |access-date=16 March 2010 |archive-date=6 March 2019 |archive-url=https://web.archive.org/web/20190306044341/http://www.justwartheory.com |url-status=usurped }}</ref>

The just war tradition addresses the morality of the use of force in two parts: when it is right to resort to armed force (the concern of ''[[jus ad bellum]]'') and what is acceptable in using such force (the concern of ''[[jus in bello]]'').<ref>{{cite web|url= http://www.eppc.org/publications/pubID.1998/pub_detail.asp |title= Home > Publications > |publisher= Eppc.org |date= 1 September 1998 |access-date= 16 March 2010 |url-status= dead |archive-url= https://web.archive.org/web/20090509230737/http://www.eppc.org/publications/pubID.1998/pub_detail.asp |archive-date=9 May 2009}}</ref>

In 1869 the Russian military theorist {{ill|Genrikh Antonovich Leer|ru|Леер, Генрих Антонович}} theorized on the advantages and potential benefits of war.<ref>
{{cite book| author1 = Genrikh Antonovich Leer |title = Opyt kritiko-istoricheskogo issledovaniya zakonov isskusstva vedeniya voyny|script-title = ru:Опыт критико-исторического исследования законов искусства ведения войны |trans-title = Critico-historical research into the laws of the art of the conduct of war |publication-date = 1869 |page = 1ff | publisher=Рипол Классик |isbn = 9785458055901}}</ref>

The Soviet leader [[Vladimir Lenin]] defined only three types of just war.<ref>{{cite web|title= Just Wars in the Light of Marxism|publisher=Marxists Internet Archive|first= Erich|last= Wollenberg|url= https://www.marxists.org/history/etol/newspape/ni/vol03/no01/wollenberg.htm}}</ref>

<blockquote>But picture to yourselves a slave-owner who owned 100 slaves warring against a slave-owner who owned 200 slaves for a more "just" distribution of slaves. Clearly, the application of the term "defensive" war, or war "for the defense of the fatherland" in such a case would be historically false, and in practice would be sheer deception of the common people, of philistines, of ignorant people, by the astute slaveowners. Precisely in this way are the present-day imperialist bourgeoisie deceiving the peoples by means of "national ideology" and the term "defense of the fatherland" in the present war between slave-owners for fortifying and strengthening slavery.<ref>{{cite web|title=Socialism and War, ch. 1|publisher=Marxists Internet Archive|first= Vladimir|last= Lenin |url= https://www.marxists.org/archive/lenin/works/1915/s-w/ch01.htm}}</ref></blockquote>

The [[anarcho-capitalist]] scholar [[Murray Rothbard]] (1926–1995) stated that "a ''just'' war exists when a people tries to ward off the threat of coercive domination by another people, or to overthrow an already-existing domination. A war is ''unjust'', on the other hand, when a people try to impose domination on another people or try to retain an already-existing coercive rule over them."<ref>{{cite web |url= https://www.lewrockwell.com/1970/01/murray-n-rothbard/whats-a-just-war |title=Just War |access-date=26 June 2019 |author=Murray N. Rothbard |website= lewrockwell.com}}</ref>

[[Jonathan Riley-Smith]] writes:
<blockquote>The consensus among Christians on the use of violence has changed radically since the crusades were fought. The just war theory prevailing for most of the last two centuries—that violence is an evil that can, in certain situations, be condoned as the lesser of evils—is relatively young. Although it has inherited some elements (the criteria of legitimate authority, just cause, right intention) from the older war theory that first evolved around AD 400, it has rejected two premises that underpinned all medieval just wars, including crusades: first, that violence could be employed on behalf of Christ's intentions for mankind and could even be directly authorized by him; and second, that it was a morally neutral force that drew whatever ethical coloring it had from the intentions of the perpetrators.<ref>{{cite web |title= Rethinking the Crusades |publisher= Catholic Education Resource Center |first=Jonathan R. |last=Smith |url= http://www.catholiceducation.org/articles/history/world/wh0042.html | url-status = dead | archive-url = https://web.archive.org/web/20010723130919/http://www.catholiceducation.org/articles/history/world/wh0042.html |archive-date=23 July 2001}}</ref>
</blockquote>