Chemical Weapons Convention Redux

"Anonymous" commented on my post about the Chemical Weapons Convention. Here's his post (in its entirety):

With respect to Japan, the factual premise of your question "How did this treaty--this flimsy piece of paper --hold back the hand of these
terrible regimes?" is wrong. They did use chemical weapons.

According to Rodney McElroy's "Briefing Book on Chemical Weapons" (Council for a Livable World Education Fund, October, 1989), in at least 900 incidents between 1937 to 1945 Japan's Army attacked civilians and military opponents in China with mustard gas, phosgene and other CW agents. I don't know how you would define "major combat operations," but 900 incidents of CW use does not strike me as trivial.

With respect to Germany, it appears that military doctrine and organizational culture played the decisive role in the Wehrmacht's decision not to use CW.

There were strong German proponents of CW, e.g., General Hermann Ochsner. But in "Cooperation Under Fire: Anglo-German Restraint During World War II" (Cornell, 1995), Jeffrey Legro cites the "conflict between chemical warfare and the dominant thinking that emerged within the Wehrmacht on how to gain military victory" (Blitzkrieg Kultur) as the key reason for German CW restraint during the war (pp. 177ff.). Legro also argues against the explanatory power of the norms explanation (Geneva Protocol on CW) for German restraint during the war (pp. 180-184).

Let me be clear: I'm not saying that treaties are useless. But what prompted me to comment in the first place was how this post presumed, in the absence of a cursory literature review or first-hand analysis, that norms were the deciding factor in preventing Japan (which, it turns out, did use CW in at least 900 instances) and Germany from CW use in World War II.

There are three things I want to say about this. Anonymous' citation of the Briefing Book on Chemical Weapons doesn't necessarily prove his point, although I am grateful to him for pointing it out and I will look at it. My assertion was that the Japanese did not use chemical weapons in "major combat operations." Anonymous cites 900 uses, which is impressive. The uses, however, are against military and civilian targets. Combat, as I understand it, involves fighting, which implies people with weapons on both sides. Gassing civilians isn't combat. Until I get a chance to look at the Briefing Book this doesn't settle the matter.

He also cites Jeffrey Legro's work. I have to admit I am not deeply familiar with the history of chemical weapons literature. I do know, however, that Dr. Legro (who is a distinguished scholar) is an advocate of cultural influences on history (see, for example, Michaeel C. Desch, "Culture Clash: Assessing the Importance of Ideas in Security Studies" in International Security, Vol. 23, No. 1. [Summer, 1998]). It would not surprise me if Dr. Legro ascribed the non-use of chemical weapons by the Germans to the military culture of the Wehrmacht officer class.

These scholarly debates, however, don't really address the central point of what I wanted to find out. The Germans, under a regime that committed numerous immoral acts, and facing extinction (the regime was facing extinction, not the country) did not order the use of chemical weapons to try to stave off defeat. The Japanese did not use chemical weapons against the Americans in order to prevent defeat. [Why would you use chemical weapons against the Chinese, whom you were mostly beating, but not against the Americans, who were mostly beating you?] The British, faced with possible invasion and defeat, did not use chemical weapons. The French in 1940 - overrun and clearly losing - did not turn to chemical weapons. The Chinese - whose people and troops were (apparently) gassed by the Japanese - did not turn to chemical weapons. The Americans - who were faced with ever-mounting casualties in assaulting heavily defended island redoubts - did not use chemical weapons. The Italians  . . .

You get the idea. What I want to know is: happened here? Were the Japanese and Germans deterred (as some historians argue)? Were they immoral about some things, but restrained by morality when it came to chemical weapons (for some reason)? Did the use of chemical weapons go against some cultural norm that all of these officer groups had (German, Japanese, Chinese, American, British, French, etc.?)

Or was it the Chemical Weapons Convention? And if it was the CWC, how did that work? Why did it work?