Trump seemed to be a big supporter of the current Syrian regime up until the recent chemical weapons attack. But why are chemical weapons such a big deal? What's the difference between killing 100 people with a bomb and doing the same with a chemical weapon?
Chemical weapons, like certain other kinds of weapons are banned not because of people killed by them, but because of what they do to the survivors.
It's a little counterintuitive that international law prefers weapons that kill cleanly over weapons that mutilate, but it's a widespread principle. It's also a motivation behind the ban on anti-personnel mines.
(Remember that mere suspicion of possession of chemical weapons was considered grounds for invading Iraq!)
Two main problems with chemical (and biological) weapons is that their effects are usually considered unnecessarily cruel, and controlling their spread is not always possible. When exposed to a chemical weapon, only some victims die right away (depending on the weapon, this group may be very small), others have to endure days or weeks of pain. While a bomb goes off once, a chemical agent can remain in a person for a long time after exposure and keep creating new wounds (such as blisters) that require the person to stay hospitalized. Additionally, most chemical weapons can be carried on the wind or settle in the soil, so they can blow from a battlefield into civilian populations, or rescue staff coming to the area after the attack can be exposed.
Since no one else has mentioned it, another reason is that chemical weapons are most effective against people who are relatively weak. Civilians over soldiers. The old and the young over those in the middle. Lower concentrations can be fatal to children.
Any weapon that is more effective against children than soldiers is one that is going to be opposed.
This is not to disagree with any of the other answers. Other reasons are important too. This just doesn't seem to be an angle that they are exploring. But it seemed worth mentioning.
Chemical weapons are "such a big deal" mainly for historical reasons, and partly for political reasons. Prohibition of use of poisonous substances has a long history, going back to at least 1675. There's a summary of the history here. Of course, since then, many more unpleasant weapons have been invented and used. The political dimension enters because there was popular revulsion against weapons which most people did not understand; very few people have direct experience of being gassed, for example. However, weapons which cause equal suffering, such as napalm, are not prohibited (use of napalm against civilians is banned by a UN convention, but not against soldiers). "Dum-dum" (i.e. expanding) bullets are a clear example of the illogicality of bans on certain types of weapons. Dum-dum bullets are outlawed in war since the Hague Convention of 1899; but they are used against civilians by US police forces.
There is a disproportionate cost in the development, maintenance, use, disposal, and cleanup of these weapons.
Not just in material wealth, but there are also significant environmental repercussions, medical costs, and general impact on the surrounding communities.
They are also comparatively ineffective in warfare considering their other ramifications.
I have more links but not enough rep yet. The GAO study covers the monetary, environmental, and community costs of disposal quite well. Also check out the recent and relevant WMD Arms Control in the Middle East by Harald Muller.
A big part of the problem with chemical weapons is that nobody wants to admit that something relatively effective against a civilian target can be comparatively so very simple, these are generally terror weapons.
Sure, VX or Sarin are buggers to synthesize, especially if you want them as a binary, but something like mustard or dimethyl mercury is not seriously going to challenge any decent industrial chemist, or even just industrial Chlorine (Pool supply company, industrial gasses supply house), not effective against a soldier in CW gear, but against civilians?
That is why the hammer must be brought down on anyone using these things, it is not because they are militarily particularly effective, it is because if you are targeting the unprepared civilians they are very effective terror weapons for non state level actors and nobody wants the idea that you can get away with that gaining currency.
From a military perspective, if you are on the loosing side in an ideological/civil/religious war, weapons which cause long term wounding are in some sense more effective then killing weapons simply because they cause the winning side a continuing liability. No winning side likes that (Blinding weapons are banned for the same reason, VERY easy to build today (Think parts from Ebay), but no winning side benefits from letting anyone get away with it).
The equivalence with nuclear and bio is largely a political thing to put these into the 'oh hell no' category, because otherwise the barrier to entry against a civil target is uncomfortably low (Unlike nuclear and bio).
Personally I think the missile attack was on the wrong target, finding out where Assad was going to be half an hour or so in advance could not have been that hard...
The Geneva protocol, also accepted by Syria (and almost every other country including the USA) considers the use of chemical weapons to be a grave breach of the international treaty.
The main elements of the protocol are now considered by many to be part of customary international law.
You have more than a single issue here: in addition to the war, and the use of inhumane weapons, you have a breach of an international agreement.
Because they offer a means of killing lots of people (soldiers or civilians) to countries who can not possess nuclear weapons. Basically they are poor mens non-nuclear nuclear weapons.
All of the arguments put forth here against chemical or biologic weapons apply to nuclear weapons as well.
Stripping lesser countries of wmd strengthens the nuclear powers and provides them with more advantages in a conflict.
The outrage against the weapons are orchestrated by wealthy nations with modern arsenals through their media to gin up public demand against them. They do this for several reasons
- Defending against chemical weapons is a pain in the rear (requiring extensive training in the use of protective gear, decontamination kits, antidotes, etc.)
- Chemical weapons are expensive and volatile (requiring a huge infrastructure to research, manufacture, store and deploy)
- Chemical weapons can harm the force that deploys them
- Chemical weapons do much less damage to the enemy (dollar-for-dollar) than conventional weapons
Because of these practical reasons, the moral reasons were manufactured and now even the thought of purposefully killing an enemy with concentrated bug spray is seen as evil while killing that same person by stabbing him in the throat with a bayonet is perfectly fine.
Because chemical weapons are classed as a Weapon of Mass Destruction. Under US military doctrine, a chemical weapon is a biological weapon is a nuclear weapon - there is literally no distinction made between them as to consequences. One of President Obama's failures (and I say this as someone who really liked him) was that he did not act when Syria last used chemical weapons, which presumably is why they thought they could get away with it again.
It is a valid ethical question, of course, considering the way in which Syria and Russia have used barrel bombs to indiscriminately massacre civilians. But one of the consequences of widespread use of gas attacks in WWI was a global consensus that this should not happen again.
I'm not expert on this, but I would think it's largely due to the distinction between weapons that are designed to target the enemy's military and military assets, vs. weapons that target people in general?
In principle, war is meant to be conducted between militaries fighting in a battle and, civilians are not directly targeted. A gun used to shoot a solider can be targeted at that soldier. A missile used to shoot down a plane can be targeted at that plane. A bomb used to destroy a military planning facility can be targeted at that facility. In the first case - the solider is a person, yes, but he/she is considered a military asset. In the second cases, the people inside the plane and building are in many respects incidental to the destruction of the thing.
A chemical weapon targets people in its vicinity, and that vicinity is in fact variable subject to wind conditions. It doesn't do anything at all to destroy military hardware. So it's very difficult to claim it was well-targeted at military assets.
Generally civilian deaths and injuries are supposed to be minimised. Difficult to do with chemical weapons (and biological, and nuclear I might add...)
They're a big deal because they've been used extensively in the past and found to be useless except as a terror weapon against civilians:
- Low effectiveness against military forces. Even back in WWI, Chemical weapons were not a wonder weapon that resulted in major breakthroughs. Gas was super effective when first used, but once the warring parties realized what was going on, they passed out gas masks. Although it's uncomfortable to walk around everywhere with a gas mask on, it pretty much solved the chemical weapon problem. Although chemical weapons have gotten much better since then, so has protection from those weapons. Chemical protection gear is in the inventory of every modern military. Attacking with poison gas will just result in everyone suiting up. Vehicles have been protected from NBC attack since at least the 60s. This is the main reason the major military powers have all discontinued use of chemical weapons.
- High effectiveness against civilians. Civilians don't have rubber suits or gas masks (unless they live in an area under constant threat from chemical attack like Israel). They don't drive NBC protected vehicles and they don't have sealed off residences. For someone looking to kill or terrify large numbers of civilians, chemical weapons are fantastic- they deliver shocking, horrible effects over huge areas for a relatively modest investment in fuel and ordinance weight. And they don't damage buildings, vehicles or infrastructure. But the thing is, there is a pretty broad consensus that people who want to do things like this are very bad guys.
- Historical reasons- WWI involved heavy use of chemical weapons, with many fatalities and many permanently injured from chlorine, mustard gas, etc. All involved agreed that it was a pretty bad experience. During WWII, all sides were armed with far more effective chemical weapons, but mostly refrained from using them for fear of retaliation. The Japanese used them against the Chinese but that was pretty much it.
So you have a weapon that is mostly worthless for military use (although it does provide your adversary with a great excuse to escalate things once you gas him), great against civilians and produces a horrifyingly painful death and lots of sympathetic, gut-wrenching footage of dying women and children. If you use them, you're pretty much asking for it.
It's a matter of perception
You can think of war is all about death and destruction and yes there are lots of nasty things but war is not about those things.
War is about control, dominance, and submission. While a bunch of soldiers wielding assault rifles backed by armored vehicles and air support is great for keeping control over people an invisible death is all about terror and murdering.
Offensive forces are, by nature, very mobile and ideally will not keep concentrated more than the strict necessary making then bad targets for chemicals. Of course, you can use chemicals against a static force defending a position, but while mortar and bombs have an effective radius measured in yards chemicals can spread for many square miles.
They are very effective against densely populated areas making the ideal weapon for genocide. While bullets kill they are associated with engagements between two military forces, chemicals are associated with the massacre of civilians (because they are very effective for it).