The Horrors of Chemical Warfare

The Horrors of Chemical Warfare

By David E. DeCosse and Brian Patrick Green

Targeted town: Syrian residents of Khan Sheikhun, where a suspected chemical weapons attack on April 4 killed at least 86 people, among them 30 children. View full image. Photo by OMAR HAJ KADOUR/AFP/Getty Images
War is hell. But even so, there are ethical boundaries that must not be crossed. The Syrian attack, the American response, and chemical weapons.

“Even in hell, it is possible to be more or less humane, to fight with or without restraint.” So said moral philosopher Michael Walzer in his classic work Just and Unjust Wars. In using such phrasing, Walzer was making the case for an abiding, moral responsibility even in the hellishness of war. His statement can be applied to the Syrian government’s April 4 chemical weapons attack on civilians—an attack that confirms the hellishness of the Syrian civil war. And Walzer’s statement also offers a way to understand the fundamental moral motivation behind the April 6 response by the Trump administration in the form of dozens of cruise missiles launched at the Syrian air base from which the planes that carried out the sarin gas attack were launched. 

Even in the hell of the Syrian civil war, the use of chemical weapons crossed an unacceptable line of inhumanity. But how does the American response fit into larger questions of just war theory; the history of chemical weapons; and recent technical developments in such weapons? 

Moral Revulsion and the “Just War” Theory

At bottom, the American military strike appears to have been driven by an instinctive and universal moral revulsion at the use of such indiscriminate and agonizing weapons. Indeed, President Trump’s statement about the American attack dwelt on the inhumanity of the weapons. Such moral revulsion points to the moral framework undergirding just war theory—in particular to the theory’s foundation in human rights to life and liberty and to the theory’s absolute prohibition against directly attacking civilians. Of course, for years the government of Bashar al-Assad has deliberately attacked civilians by dropping barrel bombs, targeting hospitals, and laying siege to areas inhabited by civilians.

But for all the evident moral outrage of the chemical weapons attack, it’s not precisely clear what in just war theory would justify the American response. One possible ground may be what’s called “humanitarian intervention” or the “responsibility to protect.” But these ethical frameworks usually carry the suggestion of one state or a group of states intervening in a more deliberate or longstanding fashion in the affairs of another sovereign state whose government is attacking its own citizens. It doesn’t appear that the Trump administration is considering such a longstanding intervention. 

Another just war category is self-defense. The statement made by President Trump distantly referred to such a category when he said that the American cruise missile attack was based on the “vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons.” He also made oblique reference to self-defense when he referred in the same statement to the effect (for example, ISIS and refugee flows) on the United States of the ongoing instability in Syria. But the invocation of self-defense in just war theory usually involves an obvious or impending attack by an adversary. And the connection of such concerns to Syria is simply too distant to be plausible. 

What remains the most plausible ethical justification for the American response is as an act of international law enforcement—the laws in this case being the international treaty banning chemical weapons and the promise by Syria in 2013 to destroy its chemical arsenal. Of course, President Trump himself and many supporters have harshly criticized international law and related institutions, including the United Nations. But the Syrian chemical weapons attack may be a moment when the realities of evil and the abiding power of moral revulsion reveal the emptiness of a nationalism determined thus far to turn its face away from the world. 

The Syrian Attack and the History of Chemical Weapons

One reason chemical weapons are banned is because they are intrinsically indiscriminate. A gun can be aimed, though often misses, but it is in the nature of chemical weapons to blow with the wind and therefore kill indiscriminately. Poison gases are also not particularly useful against targets that are prepared to deal with them—for example, any well-equipped military since World War I. They only really work against unprepared targets, such as civilians. 

Chemical weapons are also restricted by international law, making them a weapon of rogue and untrustworthy states. Syria agreed to destroy its stockpile of chemical weapons in 2013. In using them again it has clearly violated its agreement with the international community. Assad is already a moral outcast, and this most recent attack only confirms his incorrigibility.

From a historical perspective, the Catholic Church tried to ban the crossbow in 1139, but it didn’t work. However, the idea of weapons which are “intrinsically evil” (that is, there is no way to use them morally) has stood the test of time and been secularized into international treaties. For example, in addition to chemical weapons, biological weapons, poisoned bullets, land mines, blinding lasers, and several other classes of weapon are banned by various treaties, for reasons including indiscriminacy, causing unnecessary suffering, or aiming to permanently maim their victims. 

Nuclear weapons are not banned, though by the above criteria they really ought to be. For political reasons relating to the Cold War and nuclear deterrence they are not. Similarly, some nations have agreed to ban cluster bombs, while others—including the United States—have not. In the future, lethal autonomous weapons systems (“killer robots”) may be banned, though of course that will depend on political will. 

This highlights another difficulty in weapons bans: They depend not only on the willingness and honesty of the participant nations, but also somewhat on the efficacy of the weapons. Nations are willing to agree to ban chemical weapons at least partially because they are militarily ineffective, while more effective weapons, like cluster bombs and nukes, nations are unwilling to give up.

There is also something of an “unfairness” aspect built into banned weapons—for example, that they are ranged attacks, kill in subtle ways (like poison), or are otherwise dishonorable or violate human dignity. This is related to the notion of honor in war, that one deserves to be able to defend oneself and have a chance to fight one’s enemy. We have moved far beyond the days of when a crossbow could be seen as dishonorable, but all humans still have a sense of fairness, and we can all relate to the idea of the seeming unfairness of being killed without even being given a chance to see your enemy or defend yourself.

Some may say that life, and war, are not fair. But fairness in war is important for two reasons. First, it respects the targets and acknowledges their humanity, which all humans deserve—even enemies. Second, it respects the one initiating the attack and tries to avoid permanently damaging their character and habituating them into grave evil—that of killing our fellow humans unjustly. It is not only the victims of violence who are hurt by it, but also the perpetrators, and insofar as one must cause harm to others, one should do so in a way that is measured and just, to avoid as much as possible the moral injury that may come with committing violence.

Developments in the Technology of Chemical Weapons

The advance of chemical weapon technology away from the barbaric suffering caused by blistering mustard gas first used in World War I and toward the quick death of sarin reduces the “unnecessary suffering” aspect of chemical weapons. But it does nothing to make them more discriminate or more fair. If anything, a more effectively lethal, yet still indiscriminate, weapon is more worthy of being banned because the magnitude of the harm (and unfairness) is worse.

Ultimately, the question of ethics in war is a strange and terrible topic because the best options are already closed and only bad options are left. The question only becomes one of the degree of evil we are willing to accept. However, in the midst of a terrible situation, it is still vital to maintain human decency, at least as much as is possible. Otherwise everyone involved becomes a victim.


David E. DeCosse is director of Campus Ethics Programs at the Markkula Center for Applied Ethics and adjunct associate professor of religious studies at Santa Clara University. Brian Patrick Green is assistant director of Campus Ethics Programs at the Markkula Center for Applied Ethics. He also teaches ethics in the Graduate School of Engineering at Santa Clara University. Read more about their work and the Center at


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