Before his death in a 2012 shooting incident, Chris Kyle was famous in the United States for having personally killed 255 Iraqis during his time as a sniper deployed there. His number of recorded "kills" made him the most lethal sniper in US military history. Upon returning home, his memoir American Sniper would go on to sell more than a million copies and become a New York Times bestseller. Kyle's popularity was enough that acclaimed director Steven Spielberg is producing a movie based on his life.

American Sniper begins with a scene describing Kyle killing an Iraqi woman whom he believed was about to attack US forces with a grenade - a woman he never knew but whom he described as having a "twisted soul" and who would be only the first of hundreds of Iraqis whom Kyle would go on to kill during his time in the country. In addition to his military prowess, Kyle was famously dismissive of criticisms of his actions as a Navy SEAL and was remarkably self-assured about the morality of his deeds:

"People ask me all the time, 'How many people have you killed?'... The number is not important to me. I only wish I had killed more. Not for bragging rights, but because I believe the world is a better place without savages out there taking American lives."

While he was fiercely protective of his fellow soldiers, his disdain for the Iraqis living under occupation was palpable. About them he would write in his book: "I couldn't give a flying f*** about the Iraqis. I hate the damn savages."

Kyle's comments about his actions in Iraq may be viewed by some as remarkably unreflective or simply repulsive, however, they are, in many ways, the natural by-product of the dehumanising hatred and anger that accompanies war. It is difficult to judge the effects of moral injury upon individuals who have lived for prolonged periods in an environment of daily carnage and bloodshed - a fact to which the recent video of a Syrian rebel cannibalising a government soldierattests - and there is a good argument that the ultimate outrage over the atrocities committed in Iraq should lie with the politicians and military officials who helped engineer them.

A recent New Yorker profile, however, revealed some details about Kyle that potentially make him more than a case study in the morally debasing nature of armed conflict. Of particular interest is the religious fervour which helped guide his actions in Iraq: "Like many soldiers, Kyle was deeply religious and saw the Iraq War through that prism. He tattooed one of his arms with a red crusader's cross, wanting 'everyone to know I was a Christian'."

Kyle was not alone in seeing the Iraq War through such a religious prism. Indeed, his beliefs seem to place him within a disturbing collection of high-profile US political and defence figures guided in their militarism not by rational motives but by their own openly professed fundamentalism.

Fighting for God

In the spring of 2004, a Bradley armoured vehicle drove through the streets of Samarra, sending 25mm shells crashing into Iraqi households while a US interpreter on a loudspeaker shouted the chant: "Jesus kill Mohammed." In the words of one of the men involved in the firefight: "Each time I go into combat I get closer to God." While official statistics show that military personnel are on average less likely than other citizens to identify with a particular religion, events over the past decade of war and occupation in Muslim-majority countries have shown the degree to which religious belief has played a role in these conflicts.

In their zeal to 'kill Islam'... the religious fundamentalism that helped drive the Iraq War has ended up nearly wiping out one of the most ancient Christian communities in the world.

In both Afghanistanand Iraq, local populations complained about US occupation troops attempts to proselytise Christianity, triggering investigations by army officials. In Afghanistan, a scandal was created when video was leaked showing US soldiers discussing methods to convert local Afghans. The effect of an occupying army expressly identifying itself with Christianity and actively trying to convert those under occupation was summed up by one Iraqi man in Fallujah: "We say to the occupiers to stop this… This can cause strife between the Iraqis and especially between Muslim and Christians... Please stop these things and leave our homes."

Indeed, after the social fabric of Iraq was ripped apart by occupation and civil war, the Iraqi Christian population was among the most grievously affected. Although Pope John Paul II personally dispatched an envoy to appeal to former US President George W Bush not to invade Iraq, the war proceeded and resulted in devastating consequences for the indigenous Christian population. In their zeal to "kill Islam", as one guest speaker at the US Air Force Academy put it, the religious fundamentalism that helped drive the Iraq War has ended up nearly wiping out one of the most ancient Christian communities in the world.

While the US military expressly prohibits religious proselytisation and is, in theory, a strictly secular organisation, many high-ranking officials have publicly stated their religious motivations for warfare. Lt General William Boykin, one of the most senior figures enlisted by the Bush administration to fight the "War on Terror", stated that "there is no greater threat to America than Islam" and that upon killing a Somali warlord he felt validation, because "my God was bigger than his". But such crude religiously driven chauvinism went far beyond Boykin's public sentiments alone.

Jeremy Scahill's book Dirty Wars revealed that key figures in the US defence establishment - including General Stanley McChrystal and Undersecretary of Defense for Intelligence Stephen Cambone - considered themselves "fellow travellers in the great crusade against Islam", and operated with the assumption that "any actions were justified against Muslims because you were fighting against the Caliphate". That these individuals were at the forefront of crafting and implementing some of the most brutally punitive policies of the War on Terror is suggestive of how their ideological beliefs may have helped shape their actions.

This apocalyptic religious worldview extended all the way to George W Bush, whose intelligence briefings on Iraq were reportedly laden with biblical quotes. Former French President Jacques Chirac also claimed that Bush asked him to join the Iraq invasion by appealing to the "common faith" of their countries. Chirac further claimed that Bush attempted to persuade him by saying: "Biblical prophecies are being fulfilled… this confrontation is willed by God", and citing the need to combat "Gog and Magog", Satan's agents of apocalypse described in the Old Testament.

A self-professed modern crusade

During the "War on Terror", the notorious security firm then known as Blackwater was reportedly run "as a virtual extension of the CIA", and its former CEO, Erik Prince, was a man who seemed to see his task in explicitly medieval terms. An investigation into the murder of Iraqi civilians by Blackwater contractors alleged that Prince "viewed himself as a Christian crusader tasked with eliminating Muslims and the Islamic faith from the globe". Court documents went on to state that:

"Mr Prince intentionally deployed to Iraq certain men who shared his vision of Christian supremacy, knowing and wanting these men to take every available opportunity to murder Iraqis. Many of these men used call signs based on the Knights of the Templar, the warriors who fought the Crusades… [Blackwater] executives would openly speak about going over to Iraq to 'lay Hajiis out on cardboard'."

Given the close integration of Blackwater with the overall US military effort in Iraq, Prince's comments are both disturbing and suggestive of the attitudes of many of those who helped prosecute the war. Indeed, an investigation by Wired magazine's Spencer Ackerman and Noah Shachtman revealed that, for years, Pentagon training materials instructed officers that their goal was to defeat Islam in general and reduce it to "cult-status".

Those who claim to oppose violent religious fundamentalism on principle would do well to recognise it at home before seeking it out abroad.

The training went as far to suggest the need for total war against the world's 1.4 billion Muslims and the nuclear destruction of the Islamic holy sites at Mecca and Medina. The controversy predictably triggered by the revelation of these materials resulted in the Pentagon terminating the offending courses - but not before they had been used for years in training.

It would be an error to view the US government as a monolith instead of what it really is: a cacophony of competing voices. Regardless of the ideological beliefs of many of those fighting the "War on Terror", the separation of church and state is enshrined in the US constitution and the institutions of the country are themselves essentially secular.

Having said this, there can be observed a disturbing strain of medieval religious fervour in certain quarters of the political and defence establishment - in particular when discussing the subject of military intervention in the Middle East. Viewed in this light, policies such as US patronage of Israel; justified on the basis of "shared values" - and, more dubiously, on strategic necessity - look much more clouded.

Described in its present form as a "crusader state" even by some Israeli officials, the conflict between the West and the indigenous peoples of the Middle East on this issue in many ways resembles the continuation of an ongoing, centuries-long battle over the same culturally significant strip of land. Indeed, given the public statements of many key decision-makers, an argument could be made that US policy in the region is only partly rational and in fact owes some degree of its present complexion to archaic religio-cultural sentiment.

Religion or politics?

Belligerents in any conflict have a habit of viewing their own actions as both rational and noble while describing others as being driven by various types of base fundamentalism. As noted by the liberal website Crooks and Liars, had Chris Kyle expressed the same religious sentiments about warfare as a Muslim, he would have been described as a "jihadist". However, unlike most "jihadists" who fight abroad, Kyle returned to his home country as a national hero, winning movie and book deals as well as official plaudits from major national institutions.

Despite this, just as it is wrong to blame Islam for the violence committed by political actors in its name, it would be similarly absurd to claim that Christianity was intrinsically to blame for the industrial-scale violence inflicted by Kyle and other self-professed crusaders in the "War on Terror". The citing of religious justification for essentially political acts is not the sole purview of any party, and seeking to blame religion alone for violence - to the near-exclusion of other extraneous factors - is a sign of either deep ignorance or wilful blindness.

Ultimately, however, those who claim to oppose violent religious fundamentalism on principle would do well to recognise it at home before seeking it out abroad.

Murtaza Hussain is a Toronto-based writer and analyst focused on issues related to Middle Eastern politics.