While the Syrian government has been condemned for killing people with conventional weapons, the “red line’ drawn by President Obama was the use of weapons of mass destruction, specifically chemical weapons. Those more cynical than I might suggest that this amounted to saying “we do not like that you are slaughtering people, but as long as you use conventional weapons…well, we will not do much beyond condemning you.”
While the Syrian government seemed content with conventional weapons, it has been claimed that government forces used chemical weapons. Fortunately, Secretary of State John Kerry did not use the phrase “slam dunk” when describing the matter. As this is being written, President Obama has stated that he wants to launch an attack on Syria, but he has decided to let congress make the decision. While this raises some interesting issues, I will focus on the question of whether chemical weapons change the ethics of the situation. In more general terms, the issue is whether or not chemical weapons are morally worse than conventional weapons.
In terms of general perception, chemical weapons are often regarded with more fear and disgust than conventional weapons. Part of this is historical in nature. World War I one saw the first large scale deployment of chemical weapons (primarily gas launched via artillery shells). While conventional artillery and machine guns did the bulk of the killing, gas attacks were regarded with a special horror. One reason was that the effects of gas tended to be rather awful, even compared to the wounds that could be inflicted by conventional weapons. This history of chemical weapons still seems to influence us today.
Another historically based reason, I suspect, is the ancient view that the use of poison is inherently evil or at least cowardly. In both history and literature, poisoners are rarely praised and are typically cast as villains. Even in games, such as Dungeons & Dragons, the use of poison is regarded as an inherently evil act. In contrast, killing someone with a sword or gun can be acceptable (and even heroic).
A third historically based reason is, of course, the use of poison gas by the Nazis in their attempt to implement their final solution. This would obviously provide the use of poison gas with a rather evil connection.
Of course, these historical explanations are just that—explanations. They provide reasons as to why people psychologically regard such weapons as worse than conventional weapons. What is needed is evidence for one side or the other.
Another part of this is that chemical weapons (as mentioned above) often have awful effects. That is, they do not merely kill—they inflict terrible suffering. This, then, does provide an actual reason as to why chemical weapons might be morally worse than conventional weapons. The gist of the reasoning is that while killing is generally bad, the method of killing does matter. As such, the greater suffering inflicted by chemical weapons makes them morally worse than conventional weapons.
There are three obvious replies to this. The first is that conventional weapons, such as bombs and artillery, can inflict horrific wounds that can rival the suffering inflicted by chemical weapons. The second is that chemical weapons can be designed so that they kill quickly and with minimal suffering. If the moral distinction is based on the suffering of the targets, then such chemical weapons would be morally superior to conventional weapons. However, it is worth noting that horrific chemical weapons would thus be worse than less horrific conventional (or chemical) weapons.
The third is that wrongfully killing and wounding people with conventional weapons would still be evil. Even if it is assumed that chemical weapons are somewhat worse in the suffering they inflict, it would seem that the moral red line should be the killing of people rather than killing them with chemical weapons. After all, the distinction between not killing people and killing them seems far greater than the distinction between killing people with conventional weapons and killing them with chemical weapons. For example, having soldiers machine gun everyone in a village seems to be morally as bad as having soldiers fire gas shells onto the village until everyone is dead. After all, the results are the same.
Another aspect of chemical weapons that supposedly makes them worse than conventional weapons is that they are claimed to be indiscriminate. For example, a chemical weapon is typically deployed as a gas and the gas can drift and spread into areas outside of the desired target. As another example, some chemical agents are persistent—they remain dangerous for some time after the initial attack and thus can harm and kill those who were not the intended targets. This factor certainly seems morally relevant.
The obvious reply is that conventional weapons can also be indiscriminate in this way. Bombs and shells can fall outside of the intended target area to kill and maim people. Unexploded ordinance can lie about until triggered by someone. As such, chemical weapons do not seem to necessarily worse than conventional weapons—rather it is the discrimination and persistence of the weapon that seem more important than the composition. For example, landmines certainly give chemical weapons strong competition in regards to being indiscriminate and persistent.
Thus, while a specific chemical weapon could be morally worse than a specific conventional weapon, chemical weapons are not inherently morally worse than conventional weapons.