Does religion cause wars?

This page last updated April 12th, 2016

This page in brief ….

Critics often argue that religion causes wars and thus human suffering. But does history support this, or not?

I have been able to find several authoritative works on the topic, most by neutral historians, and they generally give similar answers. About 6-10% of all wars considered have significant or predominantly religious causes. Religion was a component in many wars, but the main causes are differences in culture and greed for territory, resources or power.

It turns out that in recent times atheistic political regimes have started more wars than has religion. Both religion and atheism can be used by authoritarian or aggressive governments to support wars.

What the critics say

  • Professor of Religious Studies, Charles Kimball: More wars have been waged, more people killed, and more evil perpetrated in the name of religion than by any other institutional force in human history. The sad truth continues in our present day.
  • Richard Dawkins: My point is not that religion itself is the motivation for wars, murders and terrorist attacks, but that religion is the principal label, and the most dangerous one, by which a “they” as opposed to a “we” can be identified at all.
  • Anonymous atheist on we see religion regularly used for war, mass murder, terrorism, and even genocide

Historical studies of war and its causes

It is obvious that many factors lead to wars, and thus testing the claim that religion causes wars is difficult. Here is a summary of the best studies I could find:

University of Bradford

Researchers from the Department of Peace Studies, University of Bradford were commissioned by the BBC to summarise the historical evidence. Their findings were published in God and War: an Audit & an Exploration (2003).

The audit considers 73 major wars in the past 3 millennia, 32 of which took place in the twentieth century. It tests whether religion had a part in causing each war by examining factors such as support for the war by religious leaders and the use of religious motivation by political leaders. This is the most thorough and expert assessment I could find. Its assessments are subjective but the results are clear, and perhaps surprising:

  • Only 7 (10%) of all the wars (and the same percentage of 20th century wars) had clear religious motivation, and most had no detectable religious motivation at all. Even the Arab-Israeli wars, which had a religious component, were judged to be not primarily religious, but nationalistic.
  • The 20th century war with the greatest religious motivation (as stated by US president George W Bush) was the second Gulf War when the US and allies invaded Iraq.
  • In the 20th century, “Atheistic totalitarian states (Stalin’s Russia and Mao’s China) have perpetrated more mass murder than any state dominated by a religious faith.”. The worst war in this century, the Second World War, was judged to have only minor religious causes.
  • The authors also note the positive role of religion in the past century in pressing for non-violent resolution of conflicts.

The study concludes:

this study has concluded that very few if any wars in the past 100 years have been purely religious wars. ….. Despite the negativity around the role of religion in violent conflict, this study has demonstrated that the picture is much more complicated.

Three studies in Wikipedia

Wikipedia lists three studies which address the question:

  • Encyclopedia of Wars (2004) edited by American historians Charles Phillips and Alen Alexrod considers 1763 wars over five millennia, and conclude that 123 (7%) involve a religious conflict.
  • The Encyclopedia of War (2012), edited by Gordon Martel, concludes that 6% of the wars listed can be labelled religious wars.
  • William T. Cavanaugh concludes in Myth of Religious Violence (2009) that all wars that are classed as “religious” have secular (economic or political) ramifications.

Matthew White’s assessment

Matthew White has done an assessment of killings from wars and genocide (not exactly the same question as we are considering, but related). I don’t know anything about Matthew, but while he hasn’t documented his information as well as the above study, he appears to be a fair minded atheist whose conclusions are worth considering.

If we take only those events that can be classed as wars (not an easy distinction to draw – I have included the crusades and several civil wars), his figures show that christianity is culpable in 3 major wars in which about 10 million people died, non-christian belief systems (Nazism and Communism) are culpable in 2 wars in which 45 million people died, and a further 6 wars in which about 40 million people died have unclear culpability.

It seems to me that his figures over-simplify culpability, and he certainly considers far fewer wars than the Bradford study does, but his conclusions are not all that different: wars can be caused by religion, irreligion, or by forces where religion is irrelevant, but the worst wars (in terms of deaths) have not been caused by religion.

Other assessments of causes of war and violence

Many modern assessments of the causes of war address mainly political factors, and hardly mention religion at all.

Historian, Professor Geoffrey Blainey’s The Causes of War discusses a range of alleged causes of war which he considers are not supported by the facts, and a group of pragmatic causes which he considers to be the true causes. Religion is not among either of these groups. He references Lewis Richardson in support of a conclusion that common religious belief does not promote peace, which means differing religions do not lead to greater probability of war.

Other textbooks likewise do not list religion as a significant cause of war – e.g. Greg Cashman’s What Causes War?: An Introduction to Theories of International Conflict and Stephen Van Evera’s Causes of War.

Meic Pearse, in The Gods of War: Is Religion the Primary Cause of Violent Conflict? argues that:

  • The two principal causes of war are culture and greed for territory, resources or power. Wars fought for culture often wrongly appear to be fought for religion.
  • ‘Irreligion’ is a greater cause of war than religion.

Studies of terrorism also show that religion is not a major cause, though it can strengthen resolve to commit an act of terrorism for political reasons or a sense of injustice – see Does religion cause terrorism?

RJ Rummel made a detailed study of mass murders by governments outside of war in Death by Government, and arrives at figures of about 133 million before the 20th century and 170 million in that one century. None of the major mass murderers of the 20th century (Stalin, Mao Tse-tung, Hitler and Chiang Kai-shek), and few of those that came before, were acting on the basis of religion. Rummel concludes that the main factor in mass murders is abuse of political power and lack of freedom and democracy.

Assessments of connections between religion and war

Encyclopedia of Religion and War (2003) edited by Gabriel Palmer-Fernandez sees a stronger connection between religion and war than other sources, but gives no summary figures. It also discusses how religions sometimes oppose war.

A study of the psychology of religion and violence, Effect of Scriptural Violence on Aggression concluded that focusing on violent sections of religious scriptures can increase a person’s willingness to participate in violence: People who believe that God sanctions violence are more likely than others to behave aggressively themselves.

Fighting Words: The Origins of Religious Violence by Hector Avalos assumes the connection between religion and violence and then tries to explain it in terms of competition for scarce resources. Competition for scarce physical resources would not be a religious conflict, but Avalos argues that the exclusive claims of religion constitute a non-physical scarce resource.

The Just War And Jihad: Violence in Judaism, Christianity, And Islam, edited by RJ Hoffmann also examines the connections between religion and violence, particularly the concept of ‘just war’, without establishing historically whether religion is a major cause of war.


  • It seems clear then that the claim that religion causes war is not supported by the historical or contemporary evidence. Very few wars have a significant religious cause, and most have significant other causes.
  • Religion has been assciated with war in some time periods (e.g. in the Middle Ages) when it was allied with powerful governments, but both early and modern christianity have tended to be promotors of peace.
  • There are aspects of religious belief that can encourage some believers to take up arms.
  • Atheism has been associated with more killing in war than religion, and is most dangerous when associated with a totalitarian state.
  • Thus religion, or non-religious ’causes’ such as atheism, communism, nationalism, etc, can be used to sanction violence and war, and are at their most dangerous when combined with authoritarian or aggressive governments.

Photo by Frank Hurley, in The Heritage of the Great War.

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