RSB16Peace and Conflict: Just War, Holy War, WMD and Terrorism

Just war theory sets out when it is right to go to war and how a war must be fought. It was developed by the Christian thinkers Augustine (4th–5th century) and Thomas Aquinas (13th century), and later shaped international law.

• Going to war: a just cause (e.g. defence against attack); a legitimate authority declares it; the right intention (to restore peace, not to gain land or take revenge); a last resort; a reasonable chance of success.
• Fighting the war: proportionality (no more force than needed, and the good done must outweigh the harm); discrimination (civilians must never be targeted).
• Why it matters: it tries to limit war rather than glorify it; it protects civilians; it gives governments and citizens a test to judge whether a war is right.
• Muslim responses: Islam has its own conditions for war, set out in the Qur’an, the Sunnah and the rules of lesser jihad. Many Muslims say these are very close to just war theory, and that Islam had such rules centuries before modern international law.
• Different Muslim views: some Muslims welcome just war theory as common ground with Christians and with international law; others say Muslims should judge war by the Qur’an and Shari’ah, not by a theory from another tradition, even where the conditions agree.

Just war theory

Conditions for when going to war is right and how a war must be fought; developed by Augustine and Aquinas.

Proportionality

Using no more force than needed; the good achieved must outweigh the harm.

Discrimination (in war)

Telling combatants and civilians apart, and never targeting civilians.

Jihad means “striving” in the way of Allah. Greater jihad is the inner struggle to live well; lesser jihad is the outward struggle, which can include fighting under strict conditions.

• Just cause: self-defence, or defending people who are oppressed. Qur’an 4:75 asks: “How should ye not fight for the cause of Allah and of the feeble among men and of the women and the children…?” (Pickthall’s translation). Qur’an 22:39 gives permission to those “who fight because they have been wronged”.
• Not aggression: “begin not hostilities. Lo! Allah loveth not aggressors” (Qur’an 2:190). It may not be fought to gain land or wealth, or to force anyone to convert (2:256).
• Proper authority: declared by a legitimate leader, not by individuals or private groups.
• Last resort, and peace whenever possible: Surah 4 (the spec’s range 4:69–110) says that if enemies hold back, do not fight and offer peace, “Allah alloweth you no way against them” (4:90, Pickthall’s translation). Verse 4:94 warns believers to be careful to tell friend from foe, and not to reject someone who offers peace.
• Rules in fighting: no harm to women, children, the elderly or other non-combatants; no destroying crops, trees, animals or places of worship; prisoners must be treated well; fighting stops when the enemy wants peace (8:61).
• Reward: Qur’an 4:74 promises a reward to those who fight “in the way of Allah”, whether they are killed or victorious. Muslims stress this applies only to a struggle that meets the conditions.

The conditions of lesser jihad in mainstream Muslim teaching

Jihad

Striving or struggling in the way of Allah.

Lesser jihad

The outward struggle to defend Islam and the oppressed, which may include war under strict conditions.

Non-combatant

A person not taking part in the fighting, such as a child, an older person or most civilians.

Sunni and Shi’a Muslims agree on the rules for how war is fought, and that defence is allowed. They differ mainly on who can declare war and whether an offensive war can ever be allowed today.

• Sunni teaching: a legitimate Muslim ruler or government, advised by scholars, can declare lesser jihad. Classical Sunni scholars accepted that a caliph could lead wars beyond defence, but most Sunni scholars today teach that war is allowed only for defence or to protect the oppressed.
• Shi’a (Twelver) teaching: traditionally, only the Imam, the rightful leader descended from the Prophet Muhammad, could lead an offensive war. Twelver Shi’a believe the Twelfth Imam is hidden (in occultation), so most Shi’a scholars have taught that offensive jihad is not allowed until he returns.
• Defence in Shi’a teaching: defending Muslims and their land against attack is always allowed, and senior scholars (marja’) may call on Muslims to defend themselves.
• Shared teaching: both use the same Qur’an verses (2:190, 4:75, 8:61, 22:39) and the same rules of conduct. Shi’a Muslims also look to the example of the Imams, especially Imam Husayn, who died at Karbala in 680 resisting a ruler he believed unjust.

Sunni and Shi’a teaching on when war is allowed

Imam (Shi’a)

For Shi’a Muslims, one of the rightful leaders of the Muslim community descended from the Prophet; not the same as a mosque imam.

Occultation

The Twelver Shi’a belief that the Twelfth Imam is alive but hidden, and will return.

Marja’

A senior Shi’a scholar whose rulings many Shi’a Muslims follow.

Muslims disagree about whether any modern war could meet the conditions of a just war or lesser jihad.

• Yes, it is possible: countries and peoples are still attacked and need to defend themselves; Qur’an 4:75 still calls for protecting the oppressed; modern precision weapons can, in principle, target only combatants; international law (e.g. the Geneva Conventions) shares many of Islam’s rules.
• No, it is very hard or impossible: modern weapons, especially bombing in cities and weapons of mass destruction, almost always kill civilians, breaking discrimination; there is no single, recognised Muslim authority (caliph or, for Shi’a, the Imam) to declare jihad; wars cause refugee crises and destruction out of proportion to their aims.
• Situation ethics (Joseph Fletcher, 1966) asks what the most loving action (agape) is in each case. It might support a war that saves many lives from an aggressor, but oppose one where the harm to innocent people is greater than the good achieved.
• Muslim responses to situation ethics: many Muslims agree that mercy and the effects on people matter, but say Allah’s rules, such as never deliberately killing non-combatants, cannot be broken even if the outcome seems loving.

Situation ethics

An ethical theory (Joseph Fletcher, 1966): in each situation, do the most loving thing (agape).

Geneva Conventions

International treaties setting rules to protect civilians, the wounded and prisoners in war.

A holy war (Arabic Harb al-Maqadis) is a war fought for a religious cause, believed to have God’s approval and often promising a spiritual reward.

• Features of a holy war: fought for God or to defend the faith or its holy places; called by a religious leader; those who fight believe they will be rewarded by God.
• Some Muslims see defensive lesser jihad as a kind of holy war: it is fought “in the way of Allah”, and the Qur’an promises a reward to those who fight in it (4:74).
• Many Muslim scholars say “holy war” is the wrong idea for Islam: the Qur’an never calls war itself holy; war is at most a regrettable necessity for defence and justice. The term is linked in many people’s minds with the medieval Crusades.
• The Qur’an puts peace first: “And if they incline to peace, incline thou also to it, and trust in Allah” (Qur’an 8:61, Pickthall’s translation).
• No war to convert people: “There is no compulsion in religion” (Qur’an 2:256), so a war to spread Islam by force cannot be justified.
• Divergent views: most Muslims believe a war can be religiously justified only if it meets the conditions of lesser jihad; some argue that no modern war can be holy because none could keep those conditions; a few people claim religious backing for violence that mainstream scholars condemn.

Holy war

A war fought for a religious cause, believed to have God’s approval.

Harb al-Maqadis

Arabic for “holy war”, the term used in the spec.

The spec names two passages. Muslims read them together, and in their historical context.

• Surah 8:61: if the enemy wants peace, Muslims must accept it and trust in Allah. Many Muslims see this as the guiding principle: war ends as soon as peace is possible.
• Context of Surah 9:1–14: it was revealed when some tribes of Arabia had broken their peace treaties with the Muslims in Madinah and attacked them. It announces the end of treaties with those who broke them.
• Treaties must be kept: verse 9:4 makes an exception for those who kept their treaties: “fulfil their treaty to them till their term” (Pickthall’s translation). Verse 9:7 adds: “So long as they are true to you, be true to them.”
• Verse 9:5 allows fighting against the treaty-breakers after the sacred months. Muslim scholars stress that it must not be read alone: verse 9:6 says anyone from the enemy who asks for protection must be protected and taken to a place of safety, and verse 9:13 describes the enemy as “a folk who broke their solemn pledges… and did attack you first” (Pickthall’s translation).
• How Muslims interpret it: almost all scholars read these verses as about one historical war against people who broke treaties and attacked first, not as a general command for today. People who quote 9:5 on its own to justify violence are rejected by mainstream scholars for ignoring its context.

Treaty

A formal agreement between groups or states, e.g. to keep the peace.

Context

The situation in which a text was written, which affects what it means.

Weapons of mass destruction (WMD) can kill huge numbers of people at once and cannot tell soldiers from civilians: nuclear, chemical and biological weapons.

• Problems: they kill civilians on a massive scale; their effects (radiation, disease, poisoned land) harm future generations and the environment; they could be used by accident or fall into the wrong hands; they cost money that could relieve poverty. Nuclear weapons have been used in war only twice, on Hiroshima and Nagasaki in August 1945.
• Claimed benefits: deterrence (an enemy will not attack a country that could strike back with nuclear weapons); some argue they ended the Second World War sooner; they may let a smaller country defend itself against a larger one.
• Surah 5:32: “whosoever killeth a human being for other than manslaughter or corruption in the earth, it shall be as if he had killed all mankind” (Pickthall’s translation). WMD kill the innocent without distinction.
• Most Muslims oppose using WMD: they break the rules of lesser jihad by killing non-combatants and destroying crops and land; they cannot be proportionate.
• Muslims differ about owning them: some scholars teach that even developing or holding WMD is forbidden; others argue a Muslim country may keep them only to deter attack, pointing to Qur’an 8:60, which tells Muslims to prepare strength “that thereby ye may dismay the enemy” (Pickthall’s translation). Pakistan, a Muslim-majority country, first tested nuclear weapons in 1998 and keeps them as a deterrent.
• UK facts: the UK’s nuclear weapons system is Trident, carried by submarines. In 2021 the UK set a ceiling of 260 warheads. The Treaty on the Prohibition of Nuclear Weapons (TPNW) came into force on 22 January 2021; as of July 2026 it had 96 signatories and 75 parties. The UK has not joined it, and nor has any other country with nuclear weapons.
• Last checked: November 2026.

The arguments about weapons of mass destruction

Weapons of mass destruction (WMD)

Nuclear, chemical and biological weapons, which can kill huge numbers of people indiscriminately.

Deterrence

Keeping weapons so that an enemy is too afraid of the response to attack.

Trident

The UK’s submarine-based nuclear weapons system.

TPNW

The Treaty on the Prohibition of Nuclear Weapons (in force 2021); the UK is not a party.

The spec asks for non-religious attitudes and ethical theories that support acquiring WMD, and Muslim responses to them. Not all non-religious people agree with them.

• Utilitarianism (Jeremy Bentham and John Stuart Mill): the right action is the one that brings the greatest good (or happiness) for the greatest number. A utilitarian might argue that owning nuclear weapons prevents war between major powers, so keeping them produces the most happiness overall.
• Non-religious arguments for acquiring WMD: deterrence has helped prevent war between nuclear-armed powers since 1945; a government’s first duty is to protect its citizens; giving up weapons alone would leave a country open to threats; the weapons can be a bargaining tool for disarmament talks.
• Other non-religious views: many atheists and Humanists oppose WMD. Humanists judge by reason and consequences, and the consequences of using them would be catastrophic. The philosopher Bertrand Russell, an atheist, was the first president of the Campaign for Nuclear Disarmament (CND) in 1958.
• Muslim responses: WMD cannot be used without killing innocent people, which Qur’an 5:32 condemns, so threatening to use them is also wrong; a utilitarian calculation cannot override Allah’s rules; the money could feed the poor (Zakah, social justice); deterrence did not stop many smaller wars.
• Some Muslims partly agree: they accept that a Muslim country may keep a deterrent to protect its people (Qur’an 8:60), while still forbidding any actual use against civilians.

Utilitarianism

The ethical theory that the right action brings the greatest good for the greatest number (Bentham, Mill).

Nuclear deterrent

Nuclear weapons kept to stop an enemy attacking.

CND

The Campaign for Nuclear Disarmament, founded in Britain in 1958.

Terrorism is the unlawful use of violence or threats, usually against ordinary people, to create fear and so push towards political aims. Some people who commit it claim to act for a religion; mainstream leaders of every religion condemn it.

• Violence and war: most Muslims accept force only in defence and under the rules of lesser jihad, and believe violence outside those rules is a serious sin. A minority are pacifists.
• Malik’s Muwatta (an early collection of hadith and law by Imam Malik; the spec’s reference is 21.3.10) records instructions given by Abu Bakr, the first caliph, to his commanders: do not kill women, children or old people; do not cut down fruit trees or destroy inhabited places; do not kill animals except for food. The same chapter records the Prophet Muhammad forbidding the killing of women and children.
• Why mainstream Muslims say terrorism is forbidden: it deliberately kills non-combatants; killing one innocent person is like killing all mankind (Qur’an 5:32); it is declared by no legitimate authority; it starts hostilities (2:190); it spreads fear and corruption in the land.
• How Muslims have worked to overcome these issues: in Britain, mosques and the Muslim Council of Britain have condemned terrorist attacks and worked with police and schools; in 2010 the scholar Muhammad Tahir-ul-Qadri published a long fatwa (ruling) condemning terrorism and suicide attacks; charities such as Islamic Relief help victims of war; Muslims take part in interfaith and peace education.
• Divergent views: Muslims agree terrorism is wrong, but differ on related questions, such as whether violent resistance against an occupying army can ever be lesser jihad, and how best to prevent young people being drawn into extremism.

Violence

Using force to hurt or damage people or property.

Terrorism

Unlawful violence or threats, usually against ordinary people, to create fear for political aims.

Malik’s Muwatta

An early collection of hadith and Islamic law compiled by Imam Malik ibn Anas (died 795).

Fatwa

A ruling on a point of Islamic law given by a qualified scholar.

Atheists and Humanists hold a range of views about violence, war and terrorism, based on reason, human rights and the consequences of actions.

• Violence: most Humanists believe violence is wrong except as a last resort to protect people, because it causes suffering and breaks human rights.
• War: many non-religious people accept defensive war as a last resort, judging it by its consequences and by international law; some are pacifists, believing war always causes more harm than good.
• Terrorism: non-religious people condemn terrorism because it targets innocent people and denies their human rights. Some atheists argue that religious certainty can make terrorism more likely when people believe God approves of violence.
• Muslim responses: Muslims agree that violence and terrorism are wrong and share many of the same rules (protect civilians, last resort); but they say morality rests on Allah’s commands, not only on human reason; they reject the claim that religion causes terrorism, saying terrorists break Islam’s teaching (5:32; 2:190) and that people with no religion have also used terror.
• Common ground: Muslims and Humanists often work together on refugee support, human rights and peace education.

Humanism

A non-religious approach to life based on reason, empathy and concern for others.

Human rights

Rights everyone has because they are human, such as the right to life.